Microsoft and media conglomerate Viacom have just entered a long-term partnership to provide content on each other's properties. The collaboration will bring more video and audio content to Xbox Live Marketplace, as well as casual games to Windows Live and MSN.com, with Microsoft purchasing ad content on Viacom's broadcast and online networks.

The partnership, which starts with an initial five-year contract, will bring audio and video content to MSN.com and Xbox Live Marketplace from Viacom-owned companies like MTV Networks, Paramount, and BET. Viacom will also provide casual games on MSN.com and Windows (Xbox Live Arcade was not specifically mentioned).

In return, Microsoft will purchase substantial amounts of ad content through Viacom over the next five years, with the two companies collaborating to run promotions during major events aired on MTV and BET, such as award shows. The deal is worth an estimated $500 million in business services over the initial contract period.