Is there any way to quickly scroll to top of Web page like on the iphone?
I strongly recommend Dolphin. You can add that all important feature of scrolling by web page, in a hidden (why? ) setting. Go into Features, Advanced, More and look for "Use volume key = scroll up and down by page." Once that's enabled (why isn't it default... Don't ask me! ), it's easy to just hold your volume up key and you're at the top of your page in no time.
Sometimes Dolphin gives me a "top of page" arrow automatically on the lower right of my screen while scrolling, but I won't promise it's consistent.
Hope this gives you what you need. Dolphin is awesome all around, btw.