http://psp.ign.com/articles/740/740691p1.html

"Log onto the PlayStation Store, find your games, buy them, download them, and enjoy them. The PS1 games you buy on the system will be playable both on your PSP and eventually on your PS3 console -- the same compacted file runs on both machines with the right emulation."

http://biz.gamedaily.com/industry/feature/?id=14163

"Additionally, classic PS1 titles will be made available for download on the PS3, which can then be transferred to and played on the PSP. Sometime down the line, those games will be playable on the PS3 itself, but not at launch."

and

"PD: You are correct. We'll still have that. We have the PSP downloads site now, and you're right; these PS1 games will be available either from the PSP downloads site directly, so you don't need a PS3 to get them or if you do happen to be one of the lucky guys that gets a PS3, you can download the games to your PS3 hard drive and then slide it over to your PSP. Both services will be up and running."

Lastly list:

http://www.the-magicbox.com/gaming.htm

"In the next PSP firmware upgrade, you will be able to transfer PSone games from PS3 to PSP and play."

It's for certain that you can download PS One games to your PSP either by the PS3 or the PC. It also sounds like if you own the PS One game you can transfer it over to your PSP via the PS3. I'm not sure, but I thought that's what Sony said a while ago.

The Magic Box quote might just be badly worded. It sounds like you can transfer the games you own, not just the ones you download. That would be sweet. Still if you have to download the games, that's not too bad because the price range is expected to be $5-10.

Either way it's going to rock have MK 3 and MK 4 on the go (not to mention Deception once Unchained comes out). :p