Two weeks ago Apple released the Mac OS X 10.6.7 version for the developers. Today they have announced the public release of this version and the update of this operating system is available to download on Apple support website. The new version has some key updates of the operating system including the AirPlay support.
Playing video files of different types is a problem for the generic Windows Media Player. You need different codec to play files such as .avi files which are converted using XViD or DiVX or any other such type of encoders. So VLC Media Player (VideoLAN) is one of the best players that I came across.