Well, if you have the IP address you can find out the cracker's Internet Service Provider and make a complaint to them. But to be honest, any knowledgeable cracker will be using an anonymous proxy, or else they will be using a "zombie" computer they have compromised in order to attack other computers. To be honest, it's probably not worth the trouble to make a complaint unless the same person keeps bothering you. To find out the ISP of an IP, you can dowload a tool called "Sam Spade" that will allow you to do whois lookups. www.samspade.org