My norton software detected and blocked an attacker intrusion today. i have their ip address that relates back to a yahoo server in sunnyvale, calif. how can i bust this person ?? please help.

You aren't going to have much success going down that route , this happens all the time and is why firewalls were built . Only if it happens continually would I pursue this. Unless the person is doing a DOS on your pc then I would ignore it and let your firewall do its job .

All you can do is collect the logs showing the attack and add them to a nice e-mail to the ISP providing service for that IP address range. Most have an abuse e-mail address for sending such complaints. You may not hear back from them, but its between the ISP and their customer causing a problem. Nothing else you can do. Also make sure it was an attack, not just some virus/Worm/Trojan infected machine. If you have a dynamically assigned IP address from your ISP, such "attacks" are common when you get assigned a new IP address, that was being used by an infected machine and its victims try calling it back.

I get lots of attacks <keeps my firewall busy ;)> and ive emailed by ISP a couple of times but they couldnt do much since it wasnt one of their customers , however one time it was and they informed the infected user . So as the others have said , either ignore it or email your ISP about it.