In a joint press release today, Viacom Inc. and Microsoft Corp. have announced a strategic partnership in which Viacom will supply Microsoft with movies, videos and games, and in return Microsoft will sell advertising for Viacom’s Internet sites. The agreement is for five-year and worth up to $500-million.

Under the deal, Microsoft will license, on a nonexclusive basis, entertainment content from Viacom’s MTV Networks, Paramount Pictures movie studios and BET Networks, for use on its MSN website and on its Xbox 360 game system.

Microsoft also will buy advertising on Viacom sites, and the companies will collaborate on promotions and sponsorships for award shows on MTV Networks and BET Networks, they said.

The agreement makes Microsoft the exclusive seller of remnant display advertising – or unsold ad inventory – on Viacom’s U.S. websites. Microsoft’s Atlas division will become the ad server for Viacom’s domestic websites as well, the companies said.