Sparks30,
There are certainly any number of companies that will rebuild battery packs below what the manufacturer charges for a new pack.
If you want to do the work yourself, the individual cells can be bought at plenty of places. They are not inexpensive. Figure $4.50 and up PER battery depending on what kind of batteries you have now. Sanyo and Panasonic are the big names in the rechargeable battery business. Just a quick look turned up a site that sells individual cells:
http://www2.towerhobbies.com/cgi-bin/wti0097p?MANUFACTURER=SAN&FVSEARCH=CELL+++ Hope this helps.
