ice cubes in my fry tank?

You can definately experiment with that if you want. I believe a few people do float frozen bottles of water in their tanks during the summer months and it works out pretty good. Just make sure you start off small first you don't want to drop the temperatures too far, or too quickly.

HTH
-Richer

Another option is to direct a fan to blow across the surface. The resulting evaporation will cool the water. You will need to do frequent topoff, and this won't replace the regular water changes, but it will help cool it down.

Chillers are used for more than just SW, though they are more common in SW due to the higher cost of the common SW setups. If the average FW community tank crashes, it's only a few bucks to replace (less then $50, especially for a 10), whereas even the most commonly kept SW organisms can cost that much for one animal. Many people who get into the rare, unusual, and pricy FW fish do invest in a chiller as insurance. For a small tank, the cost would be pretty extravagent though, IMO.