What browsers do you test against?
We test newly developed websites using the latest version of Microsoft Internet Explorer (currently 6.x) for Windows, Mozilla Firefox 1.x for Windows and Macintosh OS X, and Apple Safari for Macintosh OS X. We no longer test against Internet Explorer for Macintosh OS X since Microsoft is no longer developing IE for the Mac. We also validate our XHTML and CSS code using the W3C organization validation tools.
This does mean that newly developed sites may not work well with older browser versions. But almost all of the major browsers (Internet Explorer, Firefox, Netscape, Safari) can be upgraded to the latest version for free. In fact, if you are properly keeping up with your Windows XP or Windows 2000 OS updates, you are automatically being updated to the latest and greatest Internet Explorer.