IDS Information

Hi,
I am studying a part time security course and need to get a project delivered soon. The project is on Intrusion detection systems, I have the main body of the project finished. I am looking for information about how an IDS can be used as a forensic tool. I would like to get some examples of how to find evidence using host based and network based systems. On the legal side I would like to get information on the pros and cons of using IDS information as evidence, possibly real world examples of court cases where evidence was accepted or dismissed. Can anybody point me in the right direction where I can find this info or recommend a good book?
Thanks in advance