Opera Mini Web browser on the iPhone - http://itunes.apple.com/pt/app/opera-mini-web-browser/id363729560?mt=8 #iTunes
UPDATE 20100614: Ok, Opera mini is useful to have. I have used Opera as my main browser since 1996 (can it really be that long ago???), but I am still using Safari on the iPhone, mainly because text is unreadable on OM without zooming in.
Here is the Amateur Entomologists' Society page on the Mini:
... and on Safari: