There are several different ways you could do it.
Firstly, you could get a 550EX / 580EX or Canon STE2. Either of these could act as a master and your 430EX could be the slave. This would be a wireless IR connection. With this setup, you could use and control the remote flash, just as if it was attached to the camera. You keep E-TTL metering and HSS.
Another way to do it, would be to use a cord.
You could use a Canon Off-shoe cord (II or III). This would also work as if the flash was on the camera...but the cord is only 2 feet long.
You could use a PC cord with a much greater length. To do this, you would need a hot-shoe to PC connector for the camera, a PC cord, and a PC to hot-shoe connector for the flash. This setup would only give you manual flash control...but it's cheap.
The preferred 'Strobist' way to go, is to use radio triggers. To do this, you would need a radio transmitter and a receiver. There are several to choose from, Pocket Wizards being the preferred choice (expensive though). Unfortunately, the cheap (E-bay / Cactus) radio triggers do not play well with the 430EX. You could also look at the Elinchrom Skyports.
To use the radio triggers, you may also need hot-shoe to PC connectors etc.
This setup would be wireless and would give you manual flash control only.
