ChangeTracker watches the White House’s web site so you don’t have to. Whenever a page on whitehouse.gov changes, we’ll let you know — via e-mail, Twitter, or RSS.

But ChangeTracker is not a piece of software. It’s the output of a series of powerful and mostly free Web-based tools, lovingly connected over the Internet. Here’s how to do it yourself so you can track changes on any Web site on the Internets.

Quick Start:

Versionista and Yahoo! Pipes do most of the heavy lifting, so rolling your own change tracker is an easy process: simply tell Versionista to watch the page, then point a copy of our Yahoo! Pipe to Versionista:

1. Set up Versionista

Sign up for a free account at Versionista, and give it a Web page to watch. Make sure you select the option to make the site archive you’ve created public, otherwise part 3 won’t work.

2. Take a break

Grab a coffee, take a nap or finish graduate school. Unless you’re monitoring a frequently updated site, you’ll need to just sit back and wait for something to change. This may take minutes; it may take days.

3. Set up the Yahoo! Pipe

Clone the Automagic Versionista Feed Maker pipe, and run your cloned pipe, sending it the URL of Versionista public archive you created. (The URL will look like: http://versionista.com/pub/#####/1/all)

Important: If Versionista hasn’t detected any changes, the feed will be empty, but it will start filling once the page starts changing.

3½. Catch More Fish (optional)

To catch changes on more than one site, add a pipe for each domain, and shuffle the feed together by copying (what Yahoo! calls “cloning”) and editing our ChangeTracker pipe.

4. Control your feed

The output of Yahoo! Pipes is an RSS Feed with a long URL.

Routing your feed through FeedBurner will give your new tracker a nice URL and the ability to provide your and your readers with a daily e-mail digest of changes. It will also give you all kinds of statistics and useful information about your subscribers.

5. Extra credit

If you want to go whole-hog, create a Twitter account for your feed and use FriendFeed to transform tracked changes into tweets. These steps are left as an exercise to the reader.

6. Let us know?

We’d love to hear about how you’re using ChangeTracker. Drop us an email at changetracker@propublica.org or a tweet to @changetracker!