AP Central. The advanced-placement pages of the College Board. The place to go for information on the Latin AP exam. Includes downloadable files and other information, including the AP audit. Be sure to check for syllabus changes and errata notices. You can also sign onto the AP Latin discussion list (very low volume).
Bryn Mawr Classical Review. An electronic review of books pertaining to the Classical world. One can search the archives, receive reviews via email, or write reviews.
eLatin eGreek eLearn. Exchange your ideas on the role of technology in the Classics classroom here.
LatinTeach. An invaluable help for lonely Latin teachers. There is a website and a high-volume discussion list, including searchable archives. You can have contact with Latin teachers around the world. As of 2008, the page appears to be active but dormant.
Rogueclassicism. David Meadow's Classics blog. Keep up to date on what's happening all over the world.
Silva Rhetoricae. Brigham Young's excellent site on figures of speech.
Tables of Contents of Journals of Interest to Classicists. A searchable database of articles pertaining to Classics. A good first place to start research on most topics. Now housed at Rutgers University.