As you can see in the pictures, the PS3 browser looks a lot different from what we've known to come to love on the PS2. Instead, it takes a page from the PSP design book, putting that next-gen power to work with a more elegant navigation system.
You can also see that the PlayStation store looks very different from the Xbox Live Marketplace; it has a style that's much more reminiscent of the iTunes Music Store. It also looks like it has a better hierarchal structure that should make browsing the PSOne titles and downloading games a breeze.