Or is there another way to get this to work? On my blog, I have some text at the top of the sidebar with two links in it. I've given them a class to make the text stand out, but a.authorlink:visited is being overridden by #sidebar a:visited. Any advice?
Don't use !important. Users like to use their own stylesheets at times and browser support is partial. Change the order they appear in the source.
Later in the css, OR you could make the special one you want more specific. LIke you have #sidebar.visited, and you could then have #sidebar a.authorlink:visited which is more specifically named than just a.authorlink:visited.