If it does not work, feel free to ask me. The things that people tripped over so far:
silvia# ifconfig sl0
sl0: flags=10<POINTOPOINT>
        inet 136.152.64.181 --> 136.152.64.1 netmask ffffff00
netstat -r will give the routing table, in case you get
the "no route to host" messages from ping.  Mine looks like:
silvia# netstat -r Routing tables Destination Gateway Flags Refs Use IfaceMTU Rtt Netmasks: (root node) (root node) Route Tree for Protocol Family inet: (root node) => default inr-3.Berkeley.EDU UG 8 224515 sl0 - - localhost.Berkel localhost.Berkeley UH 5 42127 lo0 - 0.438 inr-3.Berkeley.E silvia.HIP.Berkele UH 1 0 sl0 - - silvia.HIP.Berke localhost.Berkeley UGH 34 47641234 lo0 - 0.438 (root node)(this is after transferring a bunch of files, your numbers should be smaller).