close to Destructoid suggests they might be doing just that -- unveiling a section of the PSP store which offers smaller games which could also be free-to-play. The source suggests that while file size will be limited at 100 megs, that's the only limit content will be given. Meaning non-game applications may also be on the cards.
These smaller games and apps are supposed to compliment the full PSP games made available digitally for the download-only PSP Go system. There are already a couple of games that fit this model, in the form of Super Stardust Portable and Everyday Shooter, both of which are under 100 megs. This sounds like a great idea to us. We'd love to see the PSP Store become as great a repository of quality downloadable-only games as the PS3 Store has become. This is still very much a rumor for now, but hopefully we'll see it come true at Gamescom in August.