Opera Mini 4.2 beta is the first third-party browser for Android. Although it's just a beta version it looks pretty good. Cnet took the new browser through its paces and it came out pretty well. They did have a problem getting the video playback feature to work but that will surely be worked out by the time it comes out of beta.
"What's distinctive and commendable of the Android-optimized build: fast speeds over T-Mobile's 3G network, a very crisp display, and quality that approaches the iPhone when it comes to viewing a zoomed-out Web page, thanks to both screen size and image clarity. The G1's two menu keys also enhance the experience, making Opera Mini's controls easy to access and navigate."
"What's distinctive and commendable of the Android-optimized build: fast speeds over T-Mobile's 3G network, a very crisp display, and quality that approaches the iPhone when it comes to viewing a zoomed-out Web page, thanks to both screen size and image clarity. The G1's two menu keys also enhance the experience, making Opera Mini's controls easy to access and navigate."