I fitted a set of Marzocchi bombers to my mates bike the other week, never done it before in my life but it was suprisingly easy!

YOu'll need a set of allan keys, a hacksaw to trim the stem to the right length, a hammer and a small flat blade screwdriver and maybe a piece of wood.

check out this link, explains what's involved.

Hope this helps.

http://www.whatmtb.com/workshopdetails.asp?id=28