Below I am replicating a long post I made on Flickr I made in response to a question from someone who just got a 430ex and asked: what do I need to get this to work off-camera? Hopefully this helps someone who tried to look at the Strobist methods and got confused.

With the 430ex there are six methods for getting the flash off-camera:

Wireless using 580EX as commander

1) triggered by a 580ex using infrared -- but then you need a 580ex. Also, what if you only want to trigger the 430ex and not have the 580ex on your camera firing?

Note: I know you can also rig some sort of periscope to your on-camera flash to get it to fire an optical slaved external flash -- or you can live with having the effect of the on-camera flash.

Wireless using ST-E2

2) Using ST-E2 -- this is an infrared transmitter that goes on your camera. But then you need that infrared transmitter and it is pricey. I don't have any experience using this.

Wired using ETTL cord

3) With a ETTL cord -- a ETTL adapter goes on top of your camera and connects to the 430ex. The longer the cord, the more expensive. IMO they don't make cords long enough to be useful. Event photographers use shorts ones so that they can mount their flashes on top of brackets. You will see this method commonly with wedding photographers.

Wired using PC cord

4) With a P/C cord -- this is an inexpensive cord that goes from a P/C female port (or from a hotshoe adapter that goes on top of your camera) to another P/C adapter that goes at the bottom of your flash on its hotshoe. The difference between this and the ETTL cord is that it only transmits 'fire' instructions, whereas ETTL information can contain instructions on power, zooming.

Wired using PC + house-hold lamp cord

4a) you can actually make a triggering cord out of lamp cord you can buy at Home Depot plus two inexpensive adapters. There is a plan on the Strobist.com blog. Look for "house-hold" or "h-h" cord.

Wireless using radio trigger

5) Radio trigger -- there are many different brands and range widely in quality and price. The difference between radio and infrared is that the receiving flash doesn't need to 'see' a flash before it knows to fire. So you can send fire instructions through walls, through ceilings, without being in line-of-sight (yes I know there are ways to trick out infrared).

The least expensive of these is the Gadget Infinity brand you can get on eBay. The most expensive are the Pocket Wizards which I use.

Update: Since I first wrote this post many more radio triggers have come onto the market including updated Chinese eBay triggers and also ones from Elinchrom ("Skyports"), Paul C. Buff, the makers of Alien Bees, ("CyberSyncs") and some Korean triggers ("SM Flashwaves"). I have personally used the Skyports and found them very solid. I had the first generation of the SM Flashwaves for a day but found they didn't work with my 430ex. Later versions apparently are okay with them.

Wireless using optical slaves

6) Inexpensive optical slaves -- works in general like infrared but are cheaper. They only know to 'fire' and do nothing else to adjust your flash.

One final note on these methods. with methods 1-3 you need a 430ex or at least a ETTL compatible flash (Metz, Sigma, etc.) With methods 4-6 any flash that can take a hotshoe adapter can be used. This opens up a world of possibilities including using old, used, inexpensive strobes that do not cost 100s of dollars. I have seven working flashes right now and only one of them cost me anything above $150 and that was the 430ex.

Accessories you will need

The basic accessories you will need regardless of the solution you choose above are:

1) a light stand -- to put your flash on so you or your buddy don't always have to hold it

2) swivel umbrella adapter -- this is an adapter that allows you to tilt and turn your flash and also put in an umbrella

3) A modifier -- modifiers include: umbrellas, beauty dishes, softboxes, snoots ... a whole world of things that help modify the light output, shape the light. You can buy these or make them yourself. Umbrellas are so inexpensive you would buy them, though.