If the truck was never driven in 4wd with the ripped boot and everything still had a lot of grease on it, it is likely fine. Check all of the ball/cage surfaces for scuffs, rust, or pitting. The traditional way of changing boots is outlined on the main page:

http://www.4x4wire.com/isuzu/tech/CVboots/?

If you go with the Mecatechs and get the whole kit with the 'pop cone', you can do it differently. Just take off the face of the hub and remove the snap ring holding the axle in place. Break loose the tie rod, upper and lower ball joints, and remove brake caliper and the entire spindle/hub assembly comes off as one piece. Obviously this needs to be done with care since the thing has some weight and wouldn't be very friendly to a shin or foot. <img src="/forums/images/graemlins/shiner.gif" alt="" />