Check fluid!!! Like Jason said, if you kept trying to rev it and make it keep moving, it probably cooked what fluid you had left. You should really drain all the fluid out and refill it. Hopefully you didn't cook the TC. Did you smell burnt fluid or anything when this happened?
Did it start dropping gears(lost 4th, then 3rd, then 2nd, then only 1st)?
If this is the case and it won't go out of 1st once the fluid is up to the proper level, you've locked up some valves in the valve body due to overheating what fluid you had left. Disassemble, take apart the valve body, clean everything reassemble valve body back to tranny. You can do this with the tranny still in the truck.
When losing fluid, the clutch plates just disengage since there is no fluid to maintain hydraulic pressure. This will keep happening until the low roller sprag is the only thing left to make you go foreward. The only thing left to burn is the pump or the TC.
Let us know how it turns out.
Blake