You kinda sound like me
I stopped not too long after PoP.
I started setting up my own server with a computer I had laying around, mainly so some friends and I could kill uber mobs and such, which really got me in the middle of a lot.
I started making some PHP-based utilities to help me manage it (instead of dealing directly with the database through Webmin). The nice thing about PHP is it's relatively easy to use once you get the hang of it, and it can be a good transition to other languages, etc. A lot of what I have contributed has resulted from that.
From there, I've started to work on quests which use Perl. The nice thing about Perl is it has quite a few similarities to PHP.
If you're not really interested in creating your own server, you can always start playing on one, and either help finding bugs, or possibly contribute to some of the existing projects out there (like PEQ). Even the smallest thing, like contributing information about how something works can be helpful (for quests, encounters, mobs, etc).
Hope this helps to point you in the right direction