Twitter related resources that are known to be very helpful.

Here are some helpful resources to get you going:
StufftoTweet.com – where you can find the hottest topics from sites like Digg, YouTube, Del.icio.us, Mashable, CNN etc.
Twellow.com – a Twitter Yellow Pages: web directory to help you find people who are interested in your topic.
TwitBacks.com – Create a semi-custom background for Twitter for free. You ought to do this for every Twitter account you create.
Hootsuite.com – a Twitter client that allows you to future post Tweets, track statistics, manage lists etc.
NearbyTweets.com – Find targeted followers tweeting about your topic in real time (can be geographically targeted).
You may find this blog post by John Reese interesting as well: http://www.income.com/blog/2009/07/09/5-reasons-why-twitter-auto-follow-is-bad-marketing/
Please let me know if you need more detailed information about Twitter.