slave flashes (vivitar 285 hv??)

Help! I am fairly new to flash photography, most of my experience is with outdoor snowsports photgraphy where it is not needed and reading al the forums about slave flashes has got me confused........

I have a 580ex on the camera and i am looking to get a couple of slave flashes. I understand everything about hooking up radio slaves but cant get my head around hooking up a couple just using cables. I would like to run a couple of 285s off camera and the 580 on it. Im assuming that the 285s have to be hooked to my pc port on my 10d somehow......

I am also confused as to the use of white light slaves....what are they and how do they work?

I would appreciate any light that can be shed on this subject!

thanks

You can't use optical slaves with a 580EX unless you put the 580 on manual mode, the ETTL preflash will trigger the slaves too early. There's lots of info in the eos bible, linked from the eos faq in this forum

If you use the PC port things should work, but you might need a hot shot adaptor if the vivitars don't have that kind of port (never used one, not sure).