At X-Fan we've got a pretty comprehensive resource of character bios:
http://x-mencomics.com/xfan/forums/forumdisplay.php?s=&
forumid=47
You can use the drop down menus at the end of the first page of entries to re-sort them to suit. You can also use the search function to find a specific character.
We're also in the process of creating team/organisation bios, creator dossiers, and issue summaries. Check them out here:
http://x-mencomics.com/xfan/forums/forumdisplay.php?s=&
forumid=46
Hope that helps!