Napster is hopping aboard the promotional-partnership bandwagon. The digital-music store is forming alliances this summer with two major brands.

The digital-music store is forming alliances this summer with two major brands, Citi and Energizer, to attract and reward customers through free download giveaways.

Citi Cards, a division of Citigroup, in conjunction with its college-student campaigns, will provide select card members with either 25 free Napster download credits or a free three-month Napster Premium subscription.

Starting this summer, Energizer will place a promotional code redeemable for one free Napster download in every 4-, 8- and 12-pack of AA Energizer e2 batteries and every 4- and 8-pack of AAA Energizer e2 batteries. The company will give away two free Napster downloads in every 12-pack of AAA Energizer e2 batteries.

The deals demonstrate a growing trend among online music stores, bundling individual song download credits with various retail products. Starting with Apple iTunes' partnership with Pepsi, other digital services have followed suit. RealNetworks inked a similar deal with Heineken, Sony Connect pacted with McDonald's and MusicMatch hooked up with Sprite.