According to Gamepro's Ben PerLee, it seems Kojima Productions are looking into releasing their latest PSP game on PSN in the future.
  

"So after I had done the preview, [Konami] had a Q/A session with us to get our complaints/ideas about the game," PerLee reported. "Other than the basics, they asked what we thought about if they released it on PSN for the PS3 as well and had online multiplayer."

Nice. This seems like a bad idea for Sony because this won't be a system seller like it should be... but awesome for people like me. 

Holy hell. Please Kojima!

I would totally love to be able to play PSP games on my PS3, although if they released it as a downloadable only title on PSN and charged the same price as a retail copy of the PSP version then Im not sure a lot of people would get it since it would be "overpriced" (though its debatable since its a full game).

ZOMG PLEEEEAAASSEE
 
I love metal gear, but I'm not buying a PSP for it.

It would be interesting to see how they price it.

This would be cool, but I'm not sure if we'd end up waiting too long for the PS3 version's release. :-/

I'm always surprised by the number of Metal Gear fans that don't own a PSP. Given that since its launch the PSP has seen Metal Gear Ac!ds 1 and 2, MGS: Portable Ops and the MGS Digital Graphic Novel, I'd have thought most fans of the series would already be in possession of one. 
 
Also, this looks great. I loved Portable Ops and this looks like more of the same, which is fine by me. I'll be looking to pick up a copy shortly after release.

"I love metal gear, but I'm not buying a PSP for it. "

I've played some of the Japanese version and I have to say that this game would be awesome on the PS3. I will buy both anyway, seeing as I'm a huge Metal Gear fan-boy

if they did it with this and portable ops i would shit brix

My problem with Peace Walker is the controls.  Camera controls with the d-pad or face buttons isn't exactly a great idea.

I totally would love to play Peace Walker because of how relevant it is to the overall storyarc. I'd of totally bought it if it got itself a simultaneous ps2 release. 
PSN though, even better! =P