Matt, I basically did what this guy did:
http://gstwins.com/gsboard/index.php?topic=39815.0, so, yeah, you remove the light from it's normal housing and re-mount it.
Snow City was able to order the bracket from their catalogue as well as the cheap-*** mirrors that he used (they're sufficient but not great, vibration issues, I'm looking to replace 'em with stock SV650 mirrors) and I picked some random turn signals that I liked the look of.
As is mentioned in the gstwins post, the bracket requires some basic bending, nothing fancy, to properly mate with the headlight, and you have to trim down at least two of the mounting posts on the headlight - I used a hacksaw, but I saw pics from one guy who used a kitchen knife and it still looked fine.
Use something soft (foamcore, cork tape, weather stripping, whatever) between the inside of the bracket and your forks to reduce the chance of the bracket and fork scratching each other.
Throw some rubber washers under the nuts that you use to mount the headlight to the bracket to reduce the light wanting to tilt (metal nut/screw against metal bracket doesn't have a great deal of grip on it's own).
It's not a bad idea to have something handy to wrap some wires up, and maybe a few zipties handy since there will be a little more exposed wiring (signals, headlight) without the fairings there. If you're feeling fancy you could get heat shrink tubing or some of those loom cable guides, but if you're cheap like me you could just wrap em in black hockey tape.
EDIT: Oh, I almost forgot, one caution: even with the light and bracket mounted as high up as they'll go before the back of the light housing hits the metal post for the tach cable, the GS500's stock suspension can be soft enough that on a particularly big bump (there's only one that would do it on my 20km commute from North York to Downtown, may be more if you live in a bumpy region), the bottom tip of the headlight can actually strike (and scratch) the front fender. So, at the very least top up your fork oil and make sure everything's in order... but really, consider a suspension upgrade. This hasn't happened once since I installed some 0.80 kg/mm Sonic Springs (you may need more, I'm light, they have a weight calculator on their site), not to mention how much they've improved the ride in general - probably the best 90$ I've spent on a motorcycle accessory, if you're on stock springs I'd seriously consider upgrading. Fairly cheap and just about the best bang for your buck as far as impact on how it rides.
Also threw in some 15W fork oil to replace the 10W stock fork oil while I was in there. Many, many how-tos on doing the springs on the gstwins site, just be take it slow and easy on those fork cap bolts.
