I'd suggest keeping all your code in an SCM repository, see this list for a selection of apps you can use. Then you can just do a simple grep through your workspace to find code that you've written before. And if it's a web interface you're after, you can use something like this (this is a web interface just for the subversion SCM system, but similar things exist for many other SCMs as well).

Of course, if you want your modules to be organised similarly to CPAN, you could always submit them to CPAN :-).