Most 99% of PC fans are 12V

Radio Shack, CompUSA sells 120V pc fans if you want to spend a couple of bucks.

Otherwise... you can use any 12V wall wart and wire your fans to it. Most will draw about 30-50 ma. Just count up your ma on your fans, and don't exceed the ma rating on the wall wart.

You can also use a PC power supply for the fans. You will have to find the 12V bus pins on the connector and then ground the pin that tells the power supply to stay on. Google power supply and pinout - you should find all you need.

Or-

Get 120V fans and you can just wire them up!

GL
HydroDynamics Reviewed by HydroDynamics on . PC Fans How can i get PC fans to work without a motherboard and all? Rating: 5