XP Pro or Win2000 are supported for the websuite (2000/2006) software packages.
In addition, at leats 512 MB of memory is recommended and 1 GB per PC is strongly recommended if a user would like to open multiple tabs and sessions and run webviews. A 17 inch monitor is preferred, and Internet Explorer 5.0 - 6.0.
This information comes straight from the ADP launch kit documentation regarding the products in question.
I'm kinda surprised that Win2k is still acceptable, since it's so close to being like W98SE, Win ME, ect, and no longer get security updates. Thanks for the update Matt, I didn't think they had renamed @net, but I wasn't sure.