RIM is advertising for a Canadian-based WebKit developer, following its acquisition of Torch Mobile (a company that developed the WebKit-based Iris Browser). Both bits of evidence irrefutably point to the fact that RIM knows the BlackBerry browser is a bit rubbish and is trying to fix it.
WebKit is a rendering engine that's used, most notably, in Apple's Safari (both on desktop and in the iPhone) and Google's Chrome browsers. It's also used in Symbian's S60 browser which can be found on Nokia, Samsung and LG handsets. Android's browser is based on WebKit, too, as is the Palm Pre's.
It's essentially the industry standard, and should help to make the BlackBerry browser more of a joy to use than its predecessor. For now, though, there's no official acknowledgement of the switch, let alone any kind of release date for a newer version of the browser, so sit tight for now and we'll let you know when we hear anything more concrete.