I've seen one in the flesh, very nice indeed. There is a newer Treo650 out now, in the States, which might explain the numbers of Treo600's showing up on eBay.
Are you going to use the phone on an Irish Network? You may need to get it unlocked...
Hi have one I love it. If you are used to Palm OS it is very easy yo pick up and use.
It has
diary
To do function (my life saver)
phone
e mail
web
camera (pretty crappy tho')
some games
An excellent calculator
A really cool word time map showing where it is nighttime
Sync with PC calendar and email
USB port for charging (can chrage off a PC or laptop ...very handy while traveling.
but the really cool thing is you can buy additional software from www.treocentral.com .
Some drawbacks
small buttons if you have big fingers look out
Doesn't support graffiti (the hand script form the palm)
By and large it’s the dog's!!
PS EDIT: I bought the unlock code on ebay for €5 I might still have it, if you need it PM me