Soda caps to offer free iTunes music.

Apple Computer and Pepsi are joining forces for another go-around of a download giveaway promotion first introduced at last year's Super Bowl.

Starting Jan. 31, specially marked 20 oz. and 1-liter bottles of Pepsi, Diet Pepsi, Pepsi Wild Cherry, Mountain Dew, Diet Mountain Dew, Mountain Dew Code Red and Sierra Mist will contain bottle caps with codes that can be redeemed for free music at the iTunes Music Store.

One in three bottles will contain a winning code. Apple and Pepsi also will be giving away free iPods as part of the promotion.

According to Apple's Web site, the sweepstakes runs through April 11 and songs must be redeemed by May 23.