Here are the food charts and lists we use:
Binky's canned food charts
Pet Food Nutritional Values list
Hobo's Guide To Nutritional Values
Dr. Lynne's Wet Food list
List of low carb gluten free Fancy Feast
On Binky's charts, stick with foods that have a number 10 or less in the carbs colum. On the Pet Food Nutritional Values Chart and Hobo's Guide, look at the %kcal from carbs column and choose foods that have a number 10 or less.
Many people start with Fancy Feast since it's available nearly everywhere and inexpensive. There are many other brands of food you can feed: Wellness, Merrick, Nature's Variety, Special Kitty, Friskies, etc.
Limit seafood to once in awhile meals. Some cats get addicted to eating fish and will refuse to eat anything else.
Don't feed any gravy-based foods unless your cat is hypoglycemic. The high carb content will raise blood glucose levels and keep them up longer than simple sugar can (corn syrup, honey, etc).
Raw pet food, either from a recipie or a commerical brand, is another option.
Low carb treats:
http://felinediabetes.com/FDMB/viewtopic.php?f=14&t=9172
People here with multiple cats just try to feed everyone low carb canned food. For those who do have to feed some dry food, they use a low carb dry food and try to feed the cats in separate rooms and make sure that the diabetic cat doesn't eat the dry. A few pieces of dry food can raise blood glucose levels pretty high in a diabetic.