Facebook will reportedly launch its iPad app during Apple's Let's Talk iPhone event, taking place today at Apple HQ in Cupertino, Calif. Facebook is also expected to launch a new version of its iPhone app featuring the new Timeline profiles, which were unveiled at f8, the secret HTML5-based mobile application platform codenamed Project Spartan, and other improvements to speed and overall design.

The app, which leaked earlier this year, has been in the pipeline for quite some time. According to Jeff Verkoeyen, a former Facebook employee and lead developer on Facebook's iPad app, the application has been feature-complete since May.

It is now nearly five months since the app was feature-complete and I haven't seen it released except for when the project was leaked on TechCrunch, Verkoeyen wrote on his personal blog on Sept. 26.

Verkoeyen may get his wish when Facebook takes the stage at Apple's massive media event Tuesday. Unfortunately, Verkoeyen won't be there to enjoy it since he now works for Facebook's premier rival Google.

Facebook's iPad app should be a big hit for Apple. Facebook's iPhone app is the most downloaded app of all time, and on the iPad, third-party iPad apps for Facebook are also among the top most popular downloads.

Apple was rumored to be working with Facebook for an iOS integration years ago, but the project was reportedly dropped due to disagreements on both sides. Apple's next mobile operating system iOS 5 will feature Twitter integration, instead.

Facebook will also reportedly announce Project Spartan, an HTML5-based platform that accommodates third-party Web developers to write apps for Facebook's mobile applications. Built to be a distribution platform for games and other Facebook apps, Project Spartan will reportedly feature quicker Notifications, bookmarking for apps, and an App Search.

The full details of Project Spartan were momentarily uploaded to Facebook's mobile developers page, where journalists and users took pictures of the page before it was taken down by a Facebook admin.

Apple's media event will be held at company headquarters for the first time. The event begins at 10 a.m. PDT.