Networks

I'm looking for a simple contact database that can be shared by multiple users and would work in Windows XP/Vista/2003 SBS Server environment. We will need to be able to enter phone numbers, addresses, notes, the usual stuff. We will also need to be able to group the contacts. It would be nice if there was a way to import & export to Outlook or at least to some intermediate, compatible format. We tried using the public Exchange folders for a bit and they just didn't work out so well.

Access, Act, Filemaker and the rest just seem way more than we need and the price just doesn't fit the basic need. Does anyone know of something else I might have missed that could fill this need?