Have you ever wished your iPhone would ring only when certain people call? Here’s how to do it:

1. Download the “Silence” ringtone here: silence.m4r
2. Copy this file into the Ringtones section of your iTunes. (Click to enlarge.)
   
   
3. Sync your iPhone with iTunes to load the ringtone.
4. On your iPhone, change your ringtone to “Silence” (under Settings -> Sounds -> Ringtone). You’ll no longer hear your phone calls.
   
   
5. For each person whose calls you still want to hear, change his or her Custom Ringtone to something audible: Click the name in your contact list, choose Ringtone, then choose something besides Default
   
   

Now you can screen calls in your sleep. Because Sunday afternoons are for napping.

UPDATE (Apr 14, 2011): I haven’t used it, but MrNumber.com appears to be an interesting service for identifying phone numbers belonging to telemarketers and blocking them.

For all the iPhone users out there: You probably know you can take a snapshot of whatever you see on your screen:

1. Briefly press the top and front buttons at the same time.
2. The screen will flash white and you’ll hear a “snapshot” sound.
3. A picture of your screen is now in your iPhone “Photos”.

I’ve found it extremely helpful to make screenshots, and I do it all the time. Here are a few reasons:

Remember an Interesting Part of a Podcast

If I’m driving and hear something I like in a podcast, I make a quick screenshot of the playback screen. When I get back to my computer, I can return to that spot in the podcast and take notes.

Save a Point on a Map

Sometimes I want to “bookmark” a location on the map before looking up something else. A screenshot is a fast way to do this.

Save a Website Address Without Interrupting Your Reading

Sometimes when I’m reading in Google Reader, I want to save the location of an article to read later. (I don’t want to leave Google Reader immediately because it has to entirely reload when I return.)

If you hold your finger on a link for a few seconds, a menu will popup with the address of the link. Sometimes I simply save a screenshot of the link, then hit Cancel and go back to my reading. Later I read the items I saved in my screenshots.

Screenshots can help you practice “ubiquitous capture” — capturing all notes, thoughts, and ideas, as they come to you, so you don’t have to keep them in your head.

Skype is one of my favorite applications. I recently used Skype to call someone in Russia and it only cost a few cents. I’ve also been studying the Skype API, which opens some interesting possibilities.

On a Mac, you can combine simple Applescript commands with simple Skype commands to open a lot of possibilities. For example, this Applescript opens Skype and calls the best taco shop in Provo, UT:

tell application “Skype”
send command “CALL +18013774710″ script name “Call the best taco shop in Provo, UT”
end tell

Skype can be scripted to automatically make phone calls, chat by video or text, or send text messages. You can also pipe in any audio or record the phone call.

This has interesting implications for companies like MacMiniColo.net that use Macs as servers (disclosure: I’m a friend of its owner and staff, and I’ve done contract work for them in the past.) Combining Applescript, Skype, shell scripting, and the say command, your server could be configured to call your cell phone when there’s an outage and tell you what the problem is.

Jon Udell’s podcast about communications-enabled business processes discusses the integration of voice calls into computer processes. They discuss examples where a business process may need approval from a supervisor. With voice integration, the computer could call a manager with a “press 1 to approve, press 2 to disapprove” message.

Skype + Applescript is sort of the poor man’s version of VOIP web services, but it’s exciting that you could actually do something interesting with it today.

For podcasters and their advertisers, tracking the size of a podcast’s audience is sticky. You can track how many people download a podcast, but who knows if they actually listened to it?

iTunes is the #1 podcasting client (57% market share last year), and additional podcatchers push podcasts into iTunes, so much of the data about podcast listenership can be found in iTunes. Advertisers just need a way to get to it.

I recently commented to Phil Windley that perhaps the iTunes XML file could be mined for listenership data. iTunes exports an XML file that contains a rating, play count, last played date, and last skip date for every song and podcast. This would be extremely valuable information for advertisers.

Phil connected me with Doug Kaye, the creator of IT Conversations, who is now exploring a way to automate the flow of this valuable iTunes information back to podcasters. After seeing the architecture he created with Amazon.com web services, I believe if anybody can do this, Doug can.

Earlier this month my brother, father, and I went to Macworld in San Francisco, waking up at 4:00 AM on Tuesday to get into Steve Jobs’s keynote. We were amazed by the iPhone — definitely under the influence of Steve’s Reality Distortion Field. It wasn’t until the Cingular CEO took the stage (snore) that I realized how tired and hungry I was.

During the keynote, I was especially impressed by the idea of developing applications for the iPhone since it runs Mac OS X. Turns out that will not be a possibility; the phone is locked from outside developers.

There are two kinds of customer lock-in: by the company or by the customer. (Who holds the knob of the one-knobbed door.)

Some companies lock in customers with contracts, cancellation fees, and being difficult to work with — mobile phone companies, cable TV companies, 1and1.com, and Tivo.

Other companies lock in customers by building phenomenal products and platforms, fostering great communities, and inspiring loyalty (even evangelism) — Apple, WordPress, Bluehost.com. Customers don’t want to leave companies like these; they lock themselves in.

At $500-600, I’m not convinced a locked-down iPhone is right for me. (Maybe.) But if I had the ability to develop applications for an always-on, Internet-connected device, I’d lock myself in.

Bonus: This Nightline video covers the announcement of the iPhone, including an exclusive with Steve Jobs. From :37 to :40 (or 5:16 to 5:13) you can see my father walking along 4th Street early Tuesday morning while my brother and I waited in line. (He brought us back Denny’s.)

This week I’m in San Francisco for Macworld. I’m looking forward to attending Steve Jobs’s keynote tomorrow, even if it means getting in line at 4:00 AM. I’m excited too that my father and brother will be joining me this year.

Today I helped Brian set up his company‘s booth, then we took the BART to the Mission district to eat at El Farolito’s. We’ll be passing out business cards for Freemacware.com as much as we can.

I’m also looking forward to a WordPress meeting on Friday.