GSwiss is a chess tournament management software. Its a tool to allot the pairings of a chess tournament using the usual "swiss" pairing system. It is basically desinged to handle a large number of players.
FreeICS is a server which allows multiple users to play chess against each other. This project is stable and in production at a number of sites. There are several sub-projects which enhance the utility of the server, starting with a tournament manager.