Well you know you need the serial cable so I won't remind you of that.
I use these two utilities.
VXUtil - handles all my Ping, TraceRoute, NSLookup queries. (free)
PockeTTY - handles all my Telnet. Believe me, its well worth the money if you want to really use Telnet on PPC. I have yet to see a free Telnet client that is worth downloading. ($40 for full, $15 for lite)