Here is an arena sounds pack Ive been using.
http://www.megaupload.com/?d=UXEGP46X
This shit is awesome. They have authentic arena sounds for every stadium, and set playlists. Use the readme to set everything up correctly, but if you put the time in its great.
Also, its worth noting that this is pretty much set up to stream from your PC. If you dont have media streaming set up, you can try to burn the files to a CD and rip them to your HDD, but there are hundreds of files so its going to take several disks since most programs that burn CDs can only do 99 tracks.