Shooting with removable flashes

I've never really been into digital photography up until recently when I broke down and bought an XT. I love it so far. My problem is every skate picture I've taken has been in natural light and never needed any more. I've been getting into sequence shots and a lot of the stuff I'd like to be shooting is in an abandoned warehouse. I've seen skateboard photographers have their flash set up on a tripod away from the camera, and until now have never wanted to know how that actually works. What would I need for this? A speed light, tripod, and what else? Also, speed lights will allow me to shoot continuous with a flash in manual mode, correct? Thanks in advance!

You will need one of two setups. You can buy a flash that will be triggered by another flash. That means that you can use your on camera flash with an auxiliary off camera flash flash that is triggered by the flash from the one on your camera.

The other set up is more sophisticated. A transmitter mounts on your hot shoe that sends a signal to a flash telling it to fire. Both setups are readily available.

Shooting continuous with a speed light is a bit trickly. The flash has to recover before it can fire the second time. The way it works is that a eloctrolitic capacitor charges up (that's what causes the whine you hear). It then discharges through the flash tube when you fire it. More expensive speed lights can fire more than one time without recharging the capacitor. You should be able to find things like this out in the spec sheet for the light you are looking at.

Off the camera flash can greatly enhance pictures. Try using delayed sync or slow sync settings. Sometimes they are called either rear curtain or front curtain sync.

Good luck