Go trolling (aw hell, make it full blown Campaign) on any/all newsgroups, lists, bbses, even distantly related to all the close subjects. IT, sysadmin, perl, cgi, mysql, Linux, XML, and any all LAMP repositories. Include the JC's, colleges, and universities. Announce a contest for the best ascii-art bull-dogging boot image generated from the best obfuscation.

That's a big place, and it's a good bet there are literally hundreds of Perl users there somewhere.

Post a notice to a web form where they can subscribe to a free announcement list concerning Perl In Houston. (Avoid the invitation for them to commit or 'join' anything at this point.)

Also post the announcement in any print publications with calendar sections.

Gather the names... mine the list.

Free beer is good too...