Tammy,
Here are the best companies that sell cool vests:
www.polarsoftice.com
www.steelevest.com
www.bodycooler.com
If you qualify financially then you can get one for free from the MS Society of America as noted above by NaeNae at (800) 532-7667 (msaa@msassociation.org).
You can also Google "CoolSport" for another option.
-Vic