If you are talking about region coded games/music/movies, then there are some restrictions. IIRC, both movies and music playing off of UMD's will be region coded, while games will not be region coded. So, AFAIK, you should be able to import a game from Japan and play it on your PSP, while movies and music will have to be from the US (or whatever region you got it from). The memory stick should work out pretty well, as long as you got the right type. There may be some work necessary in converting some of the media, but I don't think it is too hard. I've read about several people who use the PSP as a "manga viewer," and others have found it to be quite useful during train delays, watching movies off of their PSP. Of course, if you want a lot of music, movies, and pictures, you may need to get a larger memory stick or more of them. They're also pretty expensive at the moment, IMO, although I've read that they should start going down in price shortly. Hopefully they do since I may be stuck with the 32 MB one for a little while until the prices drop. Since I save my games lot, it looks like I'll have to dump a lot of them off to my PC.
I've done some reading and I should be able to view pics and the other info you provided looks on target. My DSC-T1 uses pro duo memory chips, which should be backwards compatible with the duo's - they are both the small form factor. I can't wait to check out the PSP in person - it looks beautiful. I probably won't be an early adopter though - I can't justify the use I'd get out of it right now. The GPS component may be the killer app for me.
