Not much. You could change the listening port from 6346 to something near the
top (65535) or you might find a low port open like 80 or 443, but that won't
make much difference if they are using a firewall that detects LimeWire by the
contents of packets instead of by port number.

You could also try the latest version of Azureus, which can encrypt it's
connections to prevent that sort of eavesdropping.