Okay, so Capcom hasn't completely abandoned the PS3...

...with regards to Monster Hunter. Quote from a Famitsu interview:

"Asked if it was possible that the Monster Hunter series would still come to the PS3, Capcom’s publicity department said that Capcom has a multiplatform strategy, so they cannot deny the possibility. Asked if numbered versions of the game could appear on the PSP, the response was that the PSP portable series has an important position within the company. Finally, Famitsu pointed out that some people may have purchased a PS3 once Monster Hunter 3 was announced last year. This drew a big apology from the Capcom reps, who said that PS3 owners should wait for further announcements in the series."

It seems that Capcom is feeling a little guilty about the platform switch to the Wii. They are being vague about the issue of porting MH3 to the PS3: it's possible, them having a multiplatform strategy and all, but the probability is low. At most, the PS3 will probably receive a spinoff or even an entirely different sequel, but not MH3. Don't count on it, but it's good to have hope. Especially if you're one of those who bought the PS3 for MH3. Let's just wait for those "further announcements".

At least, the PSP has "an important position within the company" and it's pretty definite that they'll keep making MH games for it. They've actually started on a new one, Monster Hunter Portable 2nd G, which was announced last TGS.