Microsoft yesterday announced the release of the final version of Windows Media Player 11. Among the new features of WMP11 is wired/wireless media sharing. Using Microsoft Windows Media Player 11 media sharing, you can stream music, pictures, and video from your computer to devices that are connected to your wired or wireless home network. And if you are using WMP 11 on Windows Vista, you can browse other shared Windows Media Player 11 libraries on your network.
WMP11 can stream WMA, WMV. MP3, AVI and MPEG files. One can also share media from folder on a network share.
Media sharing is compatible with all PlaysForSure digital media receivers as well as Microsoft Xbox 360 and MSNTV.

Streaming to XBOX 360 is pretty easy:

1) Make sure the XBOX is connected to your Wireless network (On your XBOX 360 dashboard, goto System blade\Select Network Settings\select Edit Settings\Wireless Mode\enter settings\Done)
2) Setup Media sharing in WMP11 (Goto the Library Tab\ select Media Sharing\check “Share my media”\Ok)
In the list below “Share my media to” check box, click your Xbox 360, click Allow, and then click OK. Takes a while for XBOX 360 to appear in the list.
3) That’s it. Now you can play streaming music on your XBOX 360 by going to the Media blade\Music\select Computer\On the Windows-based PC screen, select Yes, Continue. After a while, your desktop computer with the shared media name should appear. Under Select your computer, select your computer name and the shared media name. Hit Play.

Windows Media Player 11