Is writing your own code the way to go for this? Link directories are pretty common, and not that difficult. You will almost certainly find an open source version (PHP, Perl, or whatever) somewhere that will do the job fine for you. Search around the usual places: sourceforge, CPAN, maybe even the commercial script directories like hotscripts and CGI resources.
This is assuming that you don't actively want to code this, in order to further your skills. If so, then go ahead.
|A massive flamewar beneath your chosen depth has not been shown here|