My truck used to be an auto but it was converted before I bought it. The guy just broke/sawed the shifter off at the steering column. You will need a donor truck to get the clutch pedal and master-slave cylinder assembly. A clutch safety switch is good too so it wont start in gear. The drive shaft may need to be altered too. The previous owner had a lot of problems getting a good ROUND AND BALANCED drive shaft. He went through I think 2 trannys and 2 t-cases before he had a shop build a shaft from ALL NEW PIECES. Been fine ever since. You will have to make a hole for the shift lever to come through the floor and mount the shift lever boot. The cross member might have to be moved, but I would think that the holes should be in the frame. If not you will have to drill them. You will also need a clutch and flywheel. Think thats bout it except for some hours of work. It is do-able and shouldn't be to hard, mostly just a more complicated transmission swap is all.
Jordan