Advice for off-camera flash setup

I would like some advice for what exactly I need. I would like to be able to remotely fire two off camera flash units.

I currently have:
350XT
Sigma 500 DG ST flash
Sunpak 4000AF
Lightstands/umbrellas

I would like to get something along the lines of the cheap ebay radio units.
I will also need someway to attach the flashes to the lightstands, preferably with an umbrella holder also.

Would be nice to get everything from one supplier to save on shipping, but not necessary.

Thanks!

The Strobist website has some suggestions for equipment.

One note about the Sigma EF-500 DG ST - It doesn't work with garden variety hotshoe adapters. It only works on an E-TTL hotshoe or with the proper sync cord attached to the hotshoe. I don't know of any practical way to use it off-camera.