It would be a mistake, one would presume, to credit Google/V8 with prompting this new, faster model, as the Firefox people started work on their upgrade long before V8 was announced to the public. But they got it out the door first, and that counts for something.
You can download Google Chrome, which uses V8, from http://www.google.com/chrome
* Initially I described V8 as a Just In Time compiler, mislead by several evil online sources. nyte pointed out my mistake. Various sources agree with him, and I'm inclined to believe them--and him.