Eurogamer had their way with the PlayStation 3's online functionality and console UI and discovered some interesting details other than the fact that everything's free. The UI looks just like the PSP's, there are multiple sign-on identities, and there's a single login for all games. Everything's pretty much on-par with the Xbox 360's online offerings, down to the online store in which you can buy additional content for your PS3. Sony uses real money instead of Microsoft points, so there's no dollars to point conversion needed.
The store looks a lot like the Sony Connect Music Store and is much prettier than Microsoft's Marketplace, all thanks to the PS3's built-in browser. You purchase and download things here, via a shopping cart, and it works by putting money into a Wallet which then gets spent on content. Individual games like Singstar have their own stores, which is just a filtered version of the main store. All in all, Sony's online offerings are shaping up to be as good as Microsoft's, but with a much more consistent and usable UI to boot.