Joe Hewitt, the Facebook engineer behind the company’s iPhone app, stated several months ago that he intended to open-source the code he used to make that app. Unfortunately, that proved to be more difficult than he anticipated. But five months later, it seems he’s ready to go with what he calls the Three20 Project.

The project, named after the width (in pixels) of the iPhone’s screen, isn’t exactly the Facebook iPhone app open-sourced. Rather, it’s the Facebook iPhone app rebuilt by Hewitt so that it could be open-sourced, Hewitt writes on his blog. He says he’s using Three20 to make Facebook’s iPhone app for the 3.0 software — which, oddly, he says is slated for early May, even though Apple said at its iPhone 3.0 event, “this Summer.” The first day of Summer this year is June 21.

Update: Commenter Rod Begbie points out below that the 3.0 Hewitt is referring to is likely the Facebook for iPhone app, not the iPhone 3.0 software.

So what will you get by using Three20 to make your app? Well, you’ll get an easy way to create an app that has all the nice user interface components that the Facebook iPhone app contains. This includes a photo viewer, which Hewitt called his “single biggest timesink in the whole Facebook for iPhone project” — so that should come in handy.

If you’re interested, you can get all the code right now from github.

I hope Facebook isn’t waiting until May to update its iPhone app. While the app is great, it’s still based on the old Facebook, before the redesign, which some people hate — or just love to hate. And please, for the love of God, make the new Facebook iPhone app have events.