There may have been a thread like this a while ago but I have no idea where. And all of these are elsewhere... but it seemed like it might be a good idea to have a place for all of it. I'm going to list the ones's I use a lot, but please add your favorites.
Glitch Strategy Wiki - This is THE source for answers. Okay, it might not be complete and sometime it falls behind (but only because Tiny Speck works at such a fevered pace! But YOU can make it better! (Note: pages so sometimes have spoilers so beware.)
And don't forget the Glitch Strategy blog. Tons of helpful stuff.
Speaking of blog: GlitchAddict. Tons of stuff here. Not only to they cover direct Tiny Speck news and change changes, but they also cover player driven events in game. (If you are curious about exploring some of the stuff that went on in beta, browse through some history!) Also videos, a social network, and who know what else!
Zoggish. These are some great simple tools for finding stuff. Zoggish is turning into the Zagat's of Ur. Just about everyone should have the Locations page bookmarked.
Twitter: @GlitchDay tells you when a new day has dawned and @GlitchNight give you a 20 minute warning.