According to this IGN article, Sony's announced that PSP's getting a bunch of new network features later this year, including the ability to go through the PS3 to take ad-hoc multiplayer modes online. When playing in this fashion, PS3 can be used for text, chat messaging and matching, apparently.
Monster Hunter Portable 2nd G will be compatible with the new system, Sony's said, which is obviously hot news in Japan as the game's sold 2.4 million units.
In addition, PSP owners will soon be able to access the PS store directly, a long-promised feature which will allow PSP users to download games for the machine without having to use a PC or PS3.
More through the link.