parallel/series wiring

I have an interesting project going that really has a little bit to do with car audio... i am converting an arcade cabinet which i have to use 4 6x9 speakers...I've heard of people hooking up amps to pc power supplies so thats what i plan on doing. I do have some concerns however, how much power would an amp need powering 4 speakers at say 50-75 watts rms. The pc power supplies i have have 10A +12 outputs...should that be ok? also what amp should i go with and do i want series or parellel? i'm trying to do this as cheaply as possible thanks!

Why use a car stereo amp?  Get a good quality home amp or even a receiver.  You'll be much better off in the long run.

will i be able to use a home reciever with 6x9's ok?

if you wire two of them in series to one channel and the other two in series to the other channel it wont be a problem because you will be presenting a 8 ohm load to each channel which is generally the lowest recomended impedance for a home amp.

ahaaa..it all makes sense now...these 4 speakers will all be front speakers so... wire the left channel's 2 speakers in series and wire the right channel's in series and voila...8 ohms correct?

correct.  I think like 80% of the home receivers will be 8 ohms... mine's actually 4 ohm stable, but it seems to be a rarity.  But yah, a home receiver would be the best way to go.