A rather useful new tab is appearing on each app listing which quickly shows you other related or similar apps. I particularly used those words because the tab seems to use both. Yes, my X10 shows "related" apps while the Hero here shows "similar". Odd but the net result is the same, a very handy new feature added to the Market.
You should find the updated Market anytime but if yours is still not showing the new tab you can try clearing the Market cache in Settings > Applications.