Might as well start a new thread for this one.

Please post useful links to Android sites, alternative App Markets, etc.

Here are some to get started (some need registration, but it's free):

The Complete Guide to Android (PDF, Jan 2011)

Android's official Market site

SlideMe Android Community and Application Marketplace

AppBrain - Find the best Android Apps

AndroLib Apps

Android Community

TalkAndroid Forums

AndroidForums

Appolicious

Android Zoom

101 Best Android Apps

Get Android Stuff

Android.Net

Android Central

EverythingAndroid

Phandroid

Samdroid

And if you really want to get into Custom ROMs and so on,

XDA Developers