Gamers should mark their calendars for Sept. 25, when Microsoft will launch the highly anticipated final installment in the blockbuster "Halo" franchise, "Halo 3," for the Xbox 360 console.

The culmination of years of development by Microsoft-owned producers Bungie Studios, "Halo 3" has quite a bit to live up to. Its predecessor boasted the most successful video game launch in history, grossing $125 million in one day.

"On September 25, we intend to deliver a finale that will go down in entertainment history and leave people around the world with an experience that will be shared and enjoyed for years to come," said Peter Moore, Microsoft's vice president of interactive entertainment.

The game will be available in three different bundles: The standard version will retail for $59.99; a limited edition, which includes a "making of" DVD, will go for $69.99; and the $129.99 "Legendary Edition" will come packaged with a full replica of the lead character's signature headwear.

Microsoft also announced plans to release a limited-edition "Halo 3"-themed version of its Zune media player.

Some players are already getting an early taste of the game's action via a limited-time, limited-distribution public beta test that launched Tuesday night.

Fans eager to get a sneak peek can gain access via specially marked editions of "Crackdown." The test is only active through June 6. Wednesday Bungie said there had been some problems with people accessing the demo, however.

The Halo Story

The "Halo" trilogy chronicles the war between the humans and "the Covenant," a coalition of technologically advanced alien civilizations seeking to exterminate human life. Thirty-two years before the game's starting point, in an effort to develop an army of genetically-engineered soldiers to help combat their alien aggressors, the humans launched a covert military operation dubbed the "SPARTAN-II Project."

Players take on the role of Master Chief, the sole Spartan to flee a surprise attack. After a high-speed escape through space, Master Chief's escape pod crash-lands on a man-made halo that which spans the circumference of an entire planet. Players set out to save mankind, stop an alien invasion and halt the spread of a deadly parasite, all of which unfolds through brilliant gameplay and cut scenes.

While the bulk of the final chapter's storyline remains a closely guarded secret, Bungie's Web site confirmed that this installment will end the "Halo" trilogy.