Can you charge the PS3 wireless controller over regular USB?

Yes, you can charge it from any USB port.

The PS3 controllers were designed before USB charging was standardised (DCP), so they need to do some simple negotiation with the host they're connected to before they'll charge.

All the made for ps3 chargers have a simple chip in them which tells the controller it can charge up.

With respect to charging the controller with a PC: If the controller does not start charging when plugged in to your PC (for me, light was on/solid), open Device Manager, find the game controller listed under Human Interface Devices, disable the controller using the right-click context menu, unplug the controller, plug the controller back in, and the controller should start charging (light(s) on/blinking). I just verified this procedure works on Windows 8.1