Windows: If you're stuck using on old version Internet Explorer in the cubicle but have sufficient privileges to install a plug-in, Google Chrome Frame just left beta. The IE plug-in renders supported websites using Chrome's rendering engine rather than IE's, meaning that you can still get some advanced web functionality even if you're forced to use an rickety, outdated browser. Google Chrome Frame works with Internet Explorer 6, 7 and 8.
Right now Chrome Frame requires administrative rights to install the plug-in, which could be a deal-breaker if you're suffering from extreme IT lockdown, but that may not always be a problem. From Google's post (bold ours):
We've set aggressive goals for future releases: we're working on making start-up speed even faster and removing the current requirement for administrator rights to install the plug-in.
Promising. [The Chromium Blog]