As useful resources for game rules, design guides, and so forth are brought to my attention, I'll link them here. Know of a useful site? Please use the contact form to point it out!
- Board Game Geek has discussions of almost every game currently available, it seems like.
- Skotos has quite a lot of game strategy and structural analysis.
- HomeBrew.net has a collection of RPGs made available for free by their authors.