Outlook contacts

Short of buying software, can contacts be shared? As in anyone can access the contacts information on other computers?

The place I work at does not have a server. Most of the computers are in a peer to peer connection. Through this connection, any connected computer can access any files on other computers that are in a shared folder. With the some exceptions, most of the machines are some flavor of XP. Two are WinME, but those machines are not used, at least not usually. The versions of Outlook installed are mostly 2003, some 2002 and one 2007.