A FEW MORE OPTIONS
Most of you are likely already familiar with the offerings from PocketWizard, but there are other choices out there. Here's a rundown of a few.
Wein SSR XT Infrared Transmitter ($104)

Works On: Infrared
What's Hot: Talks to studio strobes
What's Not: Not solid state. Can break if dropped.
Canon ST-E2 Infrared Transmitter

Works On: Infrared
What's Hot: Works with all Canon bodies and flashes.
What's Not: Not cheap.
Photoflex Flashfire Transmitter/Receiver Kit ($100)

Works on: Radio
What's Hot: That low, low price.
What's Not: By radio standards, range is short.
Quantum FreeXwire Flash Trigger ($194 for transmitter only)
Works On: Radio
What's Hot: Compatible with the new QLink TTL system.
What's Not: Bulky.