I'm not aware of any companies accepting volunteers. There may be tax and legal liabilities involved. Have you checked out the Portland Perl Mongers, or Free Geek? Both are non-profit operations with lots of like-minded people. (Free Geek could use Perl programmers. I've slowly been refactoring a system adoption script there, but having more eyes on it would be good.)

I've taken the other route - my day job is technical but I spend my evenings writing database and application code for the Green Party of Minnesota (GPM). I imagine that if I lost my technical job that I'd get another job, (whatever paid the bills) and continue to do my volunteer programming tasks. 95% of my perl knowledge has been gathered while volunteering - it just happens to be a space with almost infinite requirements for good software. I would advise anyone looking to learn perl and do some good along the way to go find groups you are interested in and start getting involved. For me this means I'm a regular member of the GPM and I do normal member things. I'm also on the database committee and I've written the majority of the code for our state integration project. Along the way I got the opportunity to help a candidate almost win a city council race (short by 97 votes), help get our very first statewide caucuses organized and now I'm working to integrate our various disparite database systems into a single server that can serve both state and local needs but can accomodate endorsed candidates as well.

I've learned PostgreSQL, OpenBSD, Perl, mod_perl, Lex/Yacc and a whole suite of modules. In support of making our IT systems be top-flight I've spent innumerable hours learning various techniques and strategies. The net effect is that the GPM wins (tools to effect change with) and I win. Just do it, get involved and the various needs will become apparent as you learn about the organization(s).

__SIG__
printf "You are here %08x\n", unpack "L!", unpack "P4", pack "L!", B::
+svref_2object(sub{})->OUTSIDE
[download]

Having said that, though, from experience it seems that such positions are very hard to come by at the minute, either paid or otherwise. While I'm sure companies would love to have "volunteer" staff on their books (read: cheap labour), there are almost certainly legal issues they would have to address, especially as employees have rights as employees, whether they get paid or not.

Another thing to think about is how you'd finance yourself if you were doing voluntary work. You say yourself that you've been forced to accept several positions - I assume you'd need to keep a paid job as well? This could cause problems with your current employer: many contracts seem to have a clause stating that you can't carry out other "professional work that may interfere with your duties" while in employment.

I think that I'd tend to agree with some of the other comments and look for projects writing Perl that are based either online or completely outside the scope of employment. That way you have the benefit/enjoyment of coding Perl, some social events (I'd hope ..) and maybe avoid problems with your employer further down the line.

Just my thoughts ..
--Foxcub

Going with chromatic's suggestion sounds like the best idea so far. (At least for Portland area people.) If I had free time, I'd be doing that.

Instead I've been working on the House of Dreams website. Currently generated by Perl, moving to a less static version once I go through a decent design phase.

The other way to get a an internship is by networking. I worked at one company that wound up signing up an "intern" and assigning him to me. He was just learning programming, though he had a PHD in Math IIRC. He got in mainly because he was a friend of another developer.