Yesterday I came home to find two manila envelopes marked "Time Sensitive" from the IRS. I got a little wigged out at first but after I opened them I wasn't too concerned.
I'm starting up a small business (details in a few weeks) and of course I went to the IRS website to get the scoop (and an EIN). I also ordered (for free!) a small business tax workshop DVD and a tax calendar - you can go here and order one yourself if you like. I think that the IRS is doing a really great job with the educational materials for small business owners - this DVD includes a series of videos which talk about tax issues important to small businesses, which you can also watch online.
If you've ever thought about setting up your own business, this is a pretty good place to start. As a sole proprietor with no employees, my taxes will be pretty straightforward, but there's lots of guidance if your situation is more complicated.