Intrusion Detection Systems

Hello, I need some tools to monitor an ip network for intrusion detection. Can someone help me with this ? I tried before some public domain tools like argus but i need to know is someone has successfully constrcuted a good & complete intrusion detection solution (i.e monitoring, logging, real-time alarms, proactive monitoring, ..) I'm also interested in the developement of such a solutions, and i may coordinate the distributed developement effort with coordination with academic projects focusing the same goal. Best regards Hamdi