I just bought a used (obviously) 1999 BikeE AT. I like it a lot, but I am looking to do some upgrades. I'd like to:

1. Replace the Sachs derailleur with a maybe a Deore XT
2. Replace the the 7-speed hub with at least an 8-speed
3. Upgrading to an 8-speed hub would also require replacing the grip shifters; I was thinking some sort of rapid fire shifters.
4. Replacing the fork to accomodate a 20" front tire.

Has anyone done these or other upgrades to a BikeE or can you point me to site that describes how to undertake them.

Thanks!

The first three changes are just a matter of unbolting components and swapping them out. The literature that comes with the shifters and der is enough to cover the methods. www.parktool.com under the repair button has an extensive writeup on basics of bike repair and can prompt you over the sticky parts.
You might as well do 9spd as the cost differential is minimal and you get an extra gear in the 15-20mph range that is nice to have. Try places like www.hostelshoppe.com, www.poweroncycling.com and
www.gaerlan.com for forks. Don't have any suggestion as to sources otherwise. You are going to drop
some bucks on this for reasons not entirely clear.

+1 !
Sounds like you need a different 'bent. Only upgrade I've made to mine are better brakes (mine's a '96) with better pads installed and a gorilla arm brace for the rear brakes. It's also an XL frame so I added a second seat and footpegs to haul the younguns with. (as there is no other way to get a baby seat on the thing)