EDIT

DOH, you beat me to it while I was looking up links for him..

AFAIK, the "port" number listed in those firewall logs is not really the port number with ICMP as it would be with TCP or UDP. that "port" number is really the type of ICMP message recieved.

ICMP type 3 == destination unreachable
http://www.networksorcery.com/enp/pr.../icmp/msg3.htm

ICMP type 10 == router solicitation
http://www.networksorcery.com/enp/pr...icmp/msg10.htm

ICMP type 13 == timestamp request
http://www.networksorcery.com/enp/pr...icmp/msg13.htm

The destination unreachables are not unusual at all, unless you happen to know for a fact that your machine/network is not sending any traffic to the ip which is unreachable, in which case it is probably a secondary affect of someone spoofing your IP for something or other. Or I suppose they could have been trying to find out how your machine would respond to unsolicited destination unreachables, I dont know really.

The timestamp one seems a bit odd, but it might be normal traffic, I dont know.

The router solicitation seems very odd, as from my brief look at info about it that is usually traffic meant for the local network, no idea why it would arrive at your machine over the internet.