The blow off valve, or bov, is a spring-loaded valve mounted in between the turbocharger and throttle body that opens at a preset pressure. It's function is to provide an escape route for pressurized air trapped in the intake system when the turbocharger is spinning and the throttle plate suddenly closes.
The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down.
My car is well, it's like 10 lbs of shit in a 5 lb bag...
<------ Click to see what I'm workin' with. ;)