Re:
Sadly - it's probably not worth selling (I recently bought back my old ATX980) total price £100 (I think I paid over the odds for nostalgia - but was happy to do it). Personally I would keep it if I were you - It'll make you far happier to roost it round the trails once in a while than the £100 or so pounds in your pocket would.
Even back then Giant had their suspension pretty sweet. enjoy it. (although the Jett forks up front are pretty darn flexy as I recall so don't enjoy it too much!