Well, you looked on your own, so I feel you should be helped. :) Besides, that was my first foray into perl network programming as well. This seems like a dandy introduction to sockets. In the first few paragraphs it already gives you enough to write your own port scanner. Enjoy, and if we hear that you are doing evil with it... unspecified ominous mumbling :)

also, check out the IO::Socket man page!

UPDATE: more resources...

• network programming in perl
• IO::Socket manpage