According to Eurogamer, Sony Computer Entertainment will publish all future PlayStation Portable games as downloads at the same time as the retail release. Pricing details for downloadable titles have yet to be announced, but should hopefully be on par with the UMD versions.
You can expect the first of these titles on October 15, along with direct PSP access to the PlayStation Store. Providing you live in Japan, that is. As to when — or indeed if — gamers from other nations will get their turn, the jury is still out.
The twofold on/offline publishing strategy seems to be in vogue at Sony Towers at present, with the likes of Siren: Blood Curse appearing in both Blu-ray and downloadable form. Sony also plans to make a bevy of its online games available as PlayStation Network Collection bundles for PSP.