how many fans can i hook to this power supply unit?

this is the one
http://heatsinkstore.com/raid350watp4.html

Depends how many watts each fan takes up. I think

i mean how like how many available fan connectors are there? (the 4 pin ones, Molex i think is what they are called)

There are more than enough to run your fans, you can also add adapters for 3 pin connectors or molex. Why dont ya just make one of these. Its an old AT power supply, 250 watts, I just moved the switch into the case and added a terminal strip to it. Got 12 and 5 volts and it was basically free since I scavenged it from an old system given to me. Only AT power supplies can just use the switch from the comp, ATX switches from the motherboard.