It's a rumor from an untested source, but certainly an interesting rumor indeed. A poster on the N4G forums posted the image that accompanies this post, showing a supposed PlayStation 2 game store for the PlayStation Network, to be announced at E3 in a couple of weeks. It clearly shows Metal Gear Solid 2: Sons of Liberty available for purchase for £12.99, along with several other games, many of which were PlayStation 2 launch titles - Bouncer, Fantavision, etc.
Of course, this is coming from a guy on the N4G forums (a new poster at that), and an image like this could easily be faked - just making an image in Photoshop and viewing it on your television would do the trick . Sony declined to comment on rumors and speculation, as per usual, so for now we're just going to have to take this with a grain of salt. Could it happen? Most definitely...in fact it makes a whole lot of sense all things considered, but for now purely in the realm of rumor.
Playstation 2 Store [N4G Forums via CVG -Thanks Raziel!]