there is a reasonable choice. I think they are all in extras, or via a quick google search. Two alternatives I have tried are below, but I have always come back to the built in browser, for it's allround performance etc.

Tear - fast, low disk space, but does not support certain password schemes, which ruled it out for accessing my home server.

Firefox - really good browser, quite quick once loaded, and lots of features, but takes up a load of disk space. Has geo-location, and will sync history and bookmarks with firefox on your desktop.

there are others, but the above are the real alternatives to microb (which is what the builtin browser is called.)