The guessing games are officially over, as the official lineup for Lollapalooza 2010 has now been posted on the festival’s website.

Last week, the organizers of the Chicago based music festival pulled a great publicity stunt by releasing a completely blank line-up chart with Wheel of Fortune style letter boxes for each artist. While one letter was added each day, most people were left to test their “Guess That Band” skills based on the number of letters in the band names and what had been given to them, which included the letter “O” and other letters later in the week.

This year’s lineup includes some big name headliners, most notably grunge superstars Soundgarden. The band reunited after a 12 year break on Jan. 1, when lead singer Chris Cornell posted the announcement on his Twitter page. The two other big headliners are Green Day and the ubiquitous Lady Gaga.

However, the the three sub-headliners more than make up for the eye roll inducing triumvirate mentioned above. Amidst the anticipation for their as of yet unconfirmed new album, the Arcade Fire will play their first US show in quite some time. The Strokes, who recently got back together after a hiatus to focus on solo careers, will play their first gig since 2006. Lastly, everyone’s favorite French indie band, Phoenix, will continue their steady rise by bringing their arsenal of three minute pop gems to the festival.

While there’s no doubt that the crowds for those bands will be nothing short of ridiculous, there will be plenty of other great bands at Lollapalooza that will keep you busy throughout the days. There’s a wealth of indie heavy hitters, including Spoon, The National, Grizzly Bear, The New Pornographers, Dirty Projectors, The Walkmen, The xx and The Antlers. Electronic music has a very strong showing, with Hot Chip, Cut Copy, Chromeo, Fuck Buttons leading the way, along with the always entertaining Devo. And for those who like a little variety, groups like Gogol Bordello, Cypress Hill, and Slightly Stoopid will bring some of their novelties to the stage, while singer-songwriters such as Erykah Badu, Raphael Saadiq, and Jamie Lidell round out the mix. Of course, all of this only touches the surface of the lineup.

Lollapalooza will take place August 6-8 at Grant Park in Chicago. Regular three day passes are now on sale for $215, and will likely sell out long before the festival.