Wifi & Data Connection

I recently purchased the USCC HTC6800.
Is there any way to make the phone use the WiFi connection for anything that uses data when there is a 'connected' WiFi connection, and use the cellular data connection only when a WiFi connection is avaliable?

This is my first post, but it looks like a ton of good information here, along with programs.
I may have to get back into PPC software development and give back.