Touring - trek 6500 mtb

This summer I am going ride across the US following the Transamerica trail. I have a 2005 trek 6500 that I have used for mountain bike racing and am very comfortable with. I would like to convert it and use it this summer for my trip. What alterations should I make to make this bike a good touring bike?

Thanks,
Chris

i did something similar to an older mtb ... my giant yukon tourer (http://www.hoogie.co.nz/bikes/giant_yukon.htm) ... i took an old mountainbike i got really cheap and turned it into a 26" wheeled touring bike

slick tyres, racks or trailer are the most common things to do, and maybe a higher stem ... what are the wheels like? are they lightweight?

The rims are WTB Dual Duty XC according to the manufacturer are 475 grams. The Hubs are Shimano FH-475. I dont know what is considered light so I cant comment on the weight.

I recently did the same thing as Hoogie with a 93 Trek 970 mtn bike. The bike has a chromo frame and fork, top line components and wheels, and cost all of $150. I added front and rear exped racks, a leather saddle, higher stem and Conti Town and Country 1.9 x 26 tires. Total investment under $400. Older mtn bikes make great rugged tourers.

In your case, the 6500 is mid-range and I would assume the wheels will be adequate. The big question is the rack mounts, and if it has front susp it will suck up some pedaling energy and make mounting of a front rack more difficult, but not impossible (check out Old Man Mtn). Make sure chain and sprockets are in good shape, mount street tires like the Contis or maybe Armadillos, add racks and stem, and you're good to go. Basically, what Hoogie said. And have fun!

You need to ensure that the bar position is comfortable. It seems quite high already so you may not need to raise it (you may even prefer to lower it a bit).
Bar ends are useful for adding alt hand positions but aerobars are the choice for MTB tourists who do a lot of road riding.
If you are carrying a lot of luggage then you need to distrubute it between front and back but if you go ultra-light you can get away with rear luggage only.