Damn you all crack me up!!
It's funny to see many reference "script kiddies" when you don't even know what's really going on. First off, a port scan is not an intrusion attempt! You weren't even port scanned! A scan is just that, a scan, not an attempt to connect to a single port. The fact that it's from a diverse # of ips should have told you they were looking for a service.
<< nah, the FBI would have tried other ports by now, whoever is doing it should have learned that port is blocked. Not that bright but sure as hell persistant... >>
No offense, but ahhhhh.... the irony
[edit]Technical clarification: One may scan a subnet looking for a particular port on each host, so an attempt to connect to a single port could indeed be a scan, but the fact that you received the same connection attempt from many other ips suggests that it's not.[/edit]