Just got this from winbeta.org

This will bypass the message "This version of Windows Media Player can be installed only on Windows XP and Windows .NET Server." that you get on a Win2000 box. Here's a simple trick that your visitors may need to install the latest wmp9 (build 2848) on Win2k: rename the .exe to .zip, then unzip it in a new directory and run "setup_wm.exe" to launch the installation.

Download Windows Media Player 9 2848