It’s probably about to make its merry way around the blogiverse anyway, but the Internet Explorer Accessibility Toolbar really is excellent. It features most of the tools available on the Mozilla Web Developer Toolbar and a few other ones (such as links to an online version of Tidy as well as sites for checking what your page looks like to users with different types of vision impairments, and links to accessibility guidelines, view page metadata and so on and so on. Excellent stuff, especially for those developers who refuse to use anything but IE (although hey – they probably don’t care about accessibility and standards anyway ;).