Help a newbie in studio lighting - Triggering the umbrella strobes

Hello All..
I'm building a simple studio and one of my question is:
how can I trigger the umbrella strobes?
I'm using the built in light sensor, as it's triggered by my 580 exII on camera... I would like a way so I don't need the 580exII on camera... (I think it's useless to have a on camera flash on a studio right?)

Don't know if I was clear enough... Thanks!

What's an umbrella strobe? You mean a studio strobe? Or a hotshoe flash with some kind of an optical trigger?

There are a few options:
- Skyport radio system. It's not optical, but it's reliable and convenient, small, cost is $184 for a set, extra receivers are something like $100 each.
- Some kind of a tiny manual flash on your hotshoe - I can't recommend anything in particular.
- A sync cord and a hotshoe adaptor on your flashes (pain in the butt)

If your flashes have a synch port, run a cord from the camera to one of them. Most studio strobes have optical slaves and will fire once they see the first go off.

Or as mentioned above, you can use radio triggers - skyports, PocketWizards, auction cheapies. The new CyberSynch's are supposed to be nice too.

Canon makes an St-E2 so you can fire the 580 remotely via infra-red signal. You can use optical slaves for the others.

Lots and lots of options, these are just a few.