Like right now, and start researching newbie friendly providers in Vegas. You can also post on the TER Vegas discussion board looking for newbie friendly providers. You need to start the process now if you are going next week. There are some great independant providers in Vegas (and one good agency), and they are here on TER. They all need advance notice and they all screen. There are also some of the biggest ripoffs, scams, bait and switches, and upsells in Vegas. If you wait until you get there and then you are not verifiable, you will likely fall for one of the scams there, and then come back to TER crying. It happens all the time. Whatever you do, stay away from the "card flippers" and be very wary of Casino Girls.

Also take sone time to read the Self Help Center and read back on this newbie board.

Good Luck, and hope to hear from you again regarding a successful Vegas encounter, (in the form of a review perhaps) and not hear from you that you gave joined the ranks of the "scammed in Vegas." save your gambling for the tables. If you do your research right, there are "sure things" in Vegas.