Working pros and enthusiasts alike can find a lot to love about using actions in Photoshop. The re-playable lists of commands can both speed up post-processing time, and, with the right tweaking, make your look stand out and be consistent.
On the flip side, finding listings of actions that aren't clogged with poorly executed examples can be difficult.
Here are some great action directories:
Atncentral.com: the layout isn't much to look at but there is a long list of actions, almost all of which have rollover before and after effects. Most are available free of charge for download. Tutorialblog.orglist of free photoshop plugins: it's kept fairly current and covers a wider range of plugins than most other sites.