Also for freebies is
PPCSG.com.
For games, I love
Snails and
PocketNES.
For image viewers, I either use
PQView or
Peter's Viewer.
All that I have listed is either free or a very functional demo. Of course, if you actually pay for software,
you can head to
Handango.
Also, keep your eyes open around this site as there are a lot of promotional offers just for Thoughts users, and even free software sometimes (if you're lucky).