Change "Location" based on connected wifi network

I have a few locations set up: Automatic (default in OS X), Home, and School. The last two I created myself with optimized settings. For Home I have Google's DNS servers set, and or School I have all the necessary settings in order to get on their wifi network.

Since my MacBook won't get internet on some of these wifi networks when I'm set to another "Location," I'd love to have Snow Leopard automatically adjust my Location setting based on the connected wifi network. Is there a way to do this within the OS, or is there a third-party way of doing this?

Thanks!