I'm no tax expert, but the IRS Tax Map strikes me as pretty useful resource.

The folks on the AECM listserv were touting this particular tool recently. It's basically a one-stop shop for any taxpayer-related information you might need.

You can use the search engine or navigate through the alphabetized list of main topics to find what you're looking for. There are categories for FAQs, forms, publications and tax topics, and it all makes use of Extensible Markup Language (XML), Standard Generalized Markup Language (SGML) and the “topic maps” international standard to keep the information current and relevant.

Give it a test drive here, then let us know what you think.