The Unofficial Definitive Guide to the DC Universe has an index series, a chronology, Who's Who, and a history of the DCU.
DC's Alien Worlds has complete racial, platerary statistics for all DC alien races and homeworlds.   A must visit for anyone that's planning on using and DCU aliens.
Crisis on Infinite Earths a complete run-down of all twelve issues.
DC Chronology Project is an attempt to put into order all of DC's titles.
The Book of Oa has a complete bios of everyone that has ever worn a power ring.
JSA Home has the history of the JSA and bios on all the members.
DC Comics Synopsis List has synopses of most of DC modern series, issue by issue.

HEROES, the online magazine devoted exclusively to fan fiction and the nuts who write it.
MV1 Fanfiction is where is all started so long ago.  There are tons of regular titles there!
Marvel Anthology, an up and coming Marvel FanFic group
Marvel Comics 2000, yet another Marvel FanFic group
The Valiant Universe Fanfic page is another fanfiction group created by our very own Barry Reese.
All Star 2000 Thought we'd include another DC group on here. I can't really rag on them about how much better we are than them, because many of our writers do books for them as well.