Here is a link to an article about ithttp://kotaku.com/5804342/psp-games-coming-to-ps3-with-hd-visuals-extra-content and also a link to a video showing off the difference between Monster Hunter on the PSP and the PS3http://www.youtube.com/watch?v=UaZrWbkts0Q.

I think it seems about the right time to start doing it given the NGP is on the horizon. As long as they dont charge full price(50 euros+) for what are essentially old games I will be happy.