[breily]

This is also possible by tunneling through ICMP: http://www.cs.uit.no/~daniels/PingTunnel/

[randomtask]

Generally though wireless hotspots allow DNS traffic out (the DNS server isn't filtered) but not ICMP. In fact if anything is filtered it tends to be ICMP. I'm not really aware of any situations where ICMP tunnelling is useful. Anyone know of any?