I think you can use GNU Chess for the purpose of your project, very interesting indeed. Certainly, you can use GNU Chess as a computer chess player. The program uses its standard input/output for communicating with the user for interactive games or with another program. It supports two different protocols: the Chess Engine Communication Protocol (
http://home.hccnet.nl/h.g.muller/engine-intf.html) and the Universal Chess Interface (
http://wbec-ridderkerk.nl/html/UCIProtocol.html). Unless you interactively tell GNU Chess the opponent's moves, you will need to implement one of those protocols at the other end, e.g. in the vision subsystem.
If you have further questions, do not hesitate to ask again, or just contact me off-list.