Do any of you have any tips to give my muscles the most defenition for a photo shoot? Should I go to the gym prior to the shoot and "pump" them?

Look on myspace for tips

Going to the gym prior to the shoot is probably a good idea. I'm sure the photographer will know how to make your muscles look good. Lighting can be a key element, lighting that creates shadows will bring them out pretty well

Creatine!!!

Lol, you are kidding right?!? What's Creatine supposed to do for your appearance in one dose?

If you're looking for supplimentation to make you look more muscular for a photoshoot then you might as well try something like NO2 but I don't think that's the kind of advice the OP was looking for

I wouldn't recommend this, but dehydration works apparently. Don't do it though lol.

tan up, even if its fake tanning stuff.
oil up, baby oil is ok.

basically the tan darkens the valleys between muscles and the oil highlights the peaks.

take dumbbells with you and pump up RIGHT before the shoot.

should be enough. aside from also dehydrating themselves a bit, that's all pro-bodybuilders do to prep for a posedown or photo shoot.

Look into sodium load/sodium depletion phases.

Cut out all protein shakes 1-2 weeks prior as they will bloat you.

Do a search for bodybuilding contest prep and you can find what you need.

Thanks so much everyone for your advice. I have been tanning and the photographer is planning on using baby oil.

LV, could you please explain the sodium load/sodium depletion phases?
Thanks again!