Open Ports and Trojan Horses

[Steve <sgulick poboxes com>]

When I do a netstat -a I get a whole list of ports that are open on my box but
some of them are not listed in /etc/services and accoring to a security doc one
is used by netbus (12345) How do I check to see what ports are allocated to
what services and if I do have netbus on my box how do I get rid of it?

TIA
Steve