Wall Street analysts predicts Grand Theft Auto IV will easily break video game sales records this week. But one question remains: Will fans buy the game for Sony’s PlayStation 3 or Microsoft’s Xbox 360?

Both Sony (SNE) and Microsoft (MSFT) are in a heated race to win over undecided gamers who must buy one of the two consoles to play the biggest game to be released this year. The popular franchise, from Take-Two Interactive (TTWO), is expected to surpass first-week sales of $400 million, which would top Halo 3’s record of $300 million, according to Evan Wilson, an analyst with Pacific Crest Securities. “Grand Theft Auto is clearly going to be a blockbuster game,” Wilson says.

GTA IV launches Tuesday, which should result in a big boost in monthly console sales for Sony and Microsoft. Both are a distant second to market leader Nintendo with its family-friendly Wii. Nintendo, which does not offer GTA IV, sold 721,00 Wiis in the United States in March, according to market research firm NPD. The Wii sold more than the PS3 — 257,000 units — and the Xbox — 262,000 console — combined. Analysts anticipate first-week sales of about six million copies for GTA IV, which retails for $60 or $90 for a special edition.

“It’s interesting that both Sony and Microsoft are spending a lot of money to align the game with their console,” says Sam Kennedy, the editorial director for gaming publication, 1 Up Network.

Neither Microsoft nor Sony will disclose how much they have spent to promote the game, though both were quick to promote their gaming machines as the best option for GTA IV fans. The Xbox 360, with a 20 gigabyte hard drive retails for $350 while the PS3, which features Blu-ray and twice the hard drive capacity, retails for $399.

“Grand Theft Auto is a premier brand that was really established on the PlayStation platform,” says Peter Dille, senior vice president for Sony’s PlayStation Network. “Guys who love the game grew up on PlayStation. We think that they’ll vote with their wallets for the PS3.”

The GTA franchise has sold more than 65 million copies worldwide in the last 11 years. Of the previous installments, only one was made available for the Xbox platform while all the games were playable on Playstations.

A Microsoft representative says gamers will side with the Xbox because Rockstar Games, the Take-Two game studio that developed GTA IV, is making exclusive add-ons for the console.

Rockstar will release two additional game plays for those who can’t get enough of the drug trade adventures of GTA hero Niko Bellic. The first will be made availabe this fall for the Xbox. “We absolutely believe having exclusive content will boost sales,” says Xbox spokesman David Dennis. “The Grand Theft Auto franchise may have been home to the PS2, but we believe PlayStation owners will stand up and upgrade to the Xbox for [GTA IV].”

Dennis says major retailers in Europe have informed Microsoft’s sales team that GTA pre-orders favored the Xbox over PS3 by 2 to 1. He argues that this is a “strong indication” that more gamers will purchase the Xbox for the month of April.

Other Xbox perks, like Xbox Live and online rewards for top gamers, will attract console converts, he contends. “The PS2 and PS3 has an online network that’s in the low single digits. Make sure you put that number next to ours,” Dennis says. PlayStation’s online network has 3.7 million users, and Xbox Live has more than 10 million.

PlayStation’s Dille was just as quick to diss the Xbox. “Microsoft had its moment with Halo, and that moment has past,” he says. “Sure they’re touting Grand Theft Auto, but you can play it on our platform too. You want to talk about exclusive content? Sony has a very deep lineup of exclusive games like Metal Gear Solid and Grand Turismo that has the industry buzzing. The PS3 has a more exciting story going on this year.”

The two rivals can continue to throw pot shots at each other until May 15, when NPD will name a console leader for April sales in the U.S. Consumers should be happy either way. GTA IV has received fierce reviews in the gaming community. “It’s quite an amazing experience,” Kennedy says. “I can’t imagine any game being bigger this year.”