As a professional bike mechanic and long time rider of harsh sonoran desert conditions I feel compelled to respond to this. Luckily I already have on my blog.
For those in a hurry or that want me to just get to the point skip to the link and also check the end of this post for a useful tip.
Jays service driven.org blog entry on tubeless.
Complete with a great set of you tube videos that will show the original poster exactly how to make the switch and end up with a good set up utilizing his existing wheels. I do suggest a tubless compatible, tube or no tube or UST tire, different brands have different wording for it. If the original poster has WTB speed disc all mountain they have the same profile as the laser disc mountain so its the same procedure.
A word of caution. Even though they should be the same diameters tires and tubes are not. When you have tires and rims of poor tolerances paired up with out a tube the tire can separate from the rim and often does when you least want it to or expect it. This can and will lead to a spectacular crash mess and need to put in a tube while your out riding. This tends to happen with improperly done split tube and gorilla tape set ups. I am not a fan of the split tube.
Now on to sealant, which is a must if you are in a desert south west environment.
This link to my blog has info about mixing your own sealant that is better and longer lasting than stans.
Those of you who cant be bothered to mix your own sealant should look at the slime products that are specifically for tubeless bicycle tires. Its not that Stans does not work its just that there are better sealants out there that resist drying out longer, have little fibers and little rubber pellets to aid in sealing.
Useful tip that is hopefully not news to any of you:
SO your tube has a hole in, its the last one you have and you have no patches. Before you go and do something silly like stuffing the tire with grass and trying to put it on all full of grass with out a tube try taking the bad tube and tying a simple snug over hand knot in it to seal off the portion with the hole. It will be a little harder to get it back in and does not always work but this has saved me and those who ride me on more than one occasion.
When your tubeless system fails, for me its often a giant side wall cut, and you do have to put a tube in make sure you check the inside of the tire for protruding thorns you may very well have another flat with the tube.