http://www.networkundelete.com/undelete/about/undelete.asp.
The recycling bin is great for workstations, but it does nothing (AKA squat) for network shared folders. Even Novell has had the "scavenge" feature for years. NT Server does NOT have an equivalent. The link above is to a provider of some such software. I assume it works, but don't have first hand experience. Even SAMBA can have a recycle bin now...
In W2K3, Volume Shadow Copies are finally available.
Vista+ have shadow copies; however, home versions don't have a UI for accessing them. This tool lets you access them: http://www.shadowexplorer.com/