SurfRabbit…finally! A Greasemonkey replacement for Safari & Shiira (and possibly other WebKit browsers). It allows you to “customize how pages from almost any site are displayed”.
This means with this plug-in it is now possible to hide those annoying ads on Userfriendly or completely re-style your favorite news site.

Take a look at the developers homepage to read more about SurfRabbit. I’ll definitely give it a try now 🙂