Someone at the farmer's market on Saturday wanted to know how I support my tomato plants. We take 1x2s and drill large holes with a 3/4 inch bit. Then we insert bamboo poles through the holes. As the tomatoes get bigger, I use twine to attach more bamboo poles so that they're perpendicular to the existing bamboo poles. If we need to, we use pieces of used hose to tie the tomato to these supports.
The tomato cages that places like Home Depot sell are pretty much a joke when it comes to heirloom tomatoes. They just get too big. The set-up above works well and looks nice.