I always assumed the reason why you don't see adventure/campaign style mods for modern games (like DA:O) is not because of DLC, but because it's a lot of damn work now to put together that type of mod. Which is why 99% of mods for modern games are now aesthetics-related, rather than content-related.

Basically, NWN/NWN2 was the last era (to some extent, Oblivion) of campaign type mods. Maybe see if there are any active groups working on adventures for those games.

Yea, true, games are far more complex now. However you don't really see developers actively promoting a mod community by releasing mod tools anymore (like Valve's SDK or Epic MegaGames' old UnrealEdit). Some of the mods that have been released over the years were very complex to create at the time. I think with enough support and the power of modern developer tools, there would be people who would pump out some decent material.

I'd say a big part of this would be publishers wanting to make money off DLCs.

On a side note, I am absolutely ecstatic that it has been confirmed that all Witcher 2 DLCs will be free. That's proper good work.

Call or write the game development studios. See what agencies or voice work studios they work with.

How about doing voicework on newgrounds.com flash videos and games? People there are always looking for talent.

You can also try to bookmark indie sites like IndieDB and TIGSource, and keep yourself up to date on new games that may need voice actors. I remember one dev recently asked for voice actors (was it Andy Schatz?)

A friend of mine said try also odesk.com

There is a lot of mod work for Freespace 2 (fan productions with the Freespace 2 Source Code Project) and there are occasionally mods that ask for volunteer voice work.

http://www.hard-light.net/forums/

One of the Freespace 2 mods, Blue Planet: War in Heaven (Part 1), which is a great game btw, is in fact doing voice acting call for its characters and I think it is still going on.

http://www.hard-light.net/forums/index.php?topic=71181.0

No idea what's the best strategy if you plan to do it professionally and get paid for it but if it's just for fun, try the NWN/NWN2 communities. Maybe make a custom player or NPC voiceset with your own lines and upload it to NWVault or use the BioWare Social Network forums to offer your voice talent in someone's project.

Another possibility are indie adventure developers, you might find some of them at the AGS forums (Adventure Game Studio).

KotOR2 total conversion mod "Revenge of Revan" was looking for people to do VO work for the mod so you might want to take a look at that
It's one of the more successful attempts at total conversion (it's been in development since 2008) and looks like it actually gets finished unlike other KotOR total conversions that have come up and died after few months
Not sure if they need more people as the thread hasn't been updated for a while but ask them anyway, you might get lucky
http://deadlystream.com/forum/topic/235-revenge-of-revan-human-vo-sign-up-thread/

You could always submit a resume to major game developers that simply says "I'm not Nolan North", the novelty might get you a gig or two