Google has officially announced it will be releasing its own browser, named Chrome. The web comic explaining their thinking is well worth a look, but the key points are:
Each browser tab is a separate process. This means that one web page hanging or script stalling only affects that page. Your browser doesn’t crash or hang — individual tabs crash or hang and can be killed. It’s so obvious it’s brilliant. I imagine Firefox, Camino, and Safari will all follow suit as soon as they can.
It’s based on Webkit.
It’s entirely open source.