There are many other twitter resources users should be aware of. Many of these I have used in putting together the previous 10 blog entries on twitter. Here are just a few of them:
MakeUseOf Guide to Twitter
My Delicious.com Twittertools bookmarks
Twitter for Business, Twitter for Friends , by Mark Murnahan (@murnahan)
Presentation on Starting to use twitter
Just about anything on Bitrebels.com about twitter
Thanks to Ahad Bokhari (@featureblend) for suggesting this series to me.