If you’re working on historical fiction (or researching for some other reason), you chould check out this post at Madam Mayo: Guest-blogger Sanda Gulland's 5 Top Research Sites for Historical Novelists.
And writer/friend/former student/fellow former Iowan Dan Ryan offers a helpful solution to my recent, more modern research conundrum (i.e. the year 2000 vs. 2005, especially in terms of technocolgy) with these fabulous recommendations:
Here's a web site that lets you view what the Internet was like in the past:
http://www.archive.org/web/web.php
You enter a web site, and you get a list of dates from which to choose. For example, if you choose cnn.com, you get the following page: http://web.archive.org/web/*/http://cnn.com
If you have any baseball in your novel**, this site is amazing: http://www.retrosheet.org/
For example, here are the box scores for May 7th, 2005:
http://www.retrosheet.org/boxesetc/2005/05072005.htm
**As I so often do, though, alas, not in this present work-in-progress.