The folks at Dark Reading have a story on called What to Do When Your Security’s Breached.

The following are six steps you should take if you encounter a possible security breach. Some experts recommend eight, some have 10, but these are the ones that most authorities agree on. Oh, and they also agree on this: You should have done the first three steps before you had the breach.
1. Assemble an incident response team.
2. Assess the initial damage and the risk for more.
3. Develop a notification plan.
4. Begin remediating the problem.
5. Document everything.
6. Develop a strategy for stopping the next attack.

It’s worth a read. And, you should really consider working on those first three steps…