I have Adobe Premiere 6.5 - How could I put two of the SAME person on the screen at once? Ex. they each start on each end of the screen and walk past each other (Cross paths). How could I do this?

Greenscreen. but I'm guessing the original footage isn't on greenscreen?

the crossing paths bit is what makes it hard. otherwise you could confine each to one half of the screen. lock the camera. shoot twice, and matte it.

its a pain in the ass to do with premiere, but with vegas it isn't too hard.

basically, mask them both out frame by frame, cut it in half, put them next to each other. it sounds more complicated than it is, but if need be, i can make a demo when i get a chance.

Yeah, I thought of masking it frame by frame in After Effects, but that would take forever. Anybody think of a simpler way?

Use a combination of what everybody said. Do rough garbage masks where they're far apart. And when they cross, do more precise masks. Hopefully, it's only a few dozen frames. Remember, masks are keyframeable, so start with the first frame, then go to the last. Then go to the middle. Hopefully you won't have to adjust every single frame manually. This is rotoscoping.

As long as it's okay to have one person on either side of the screen, simply crop both images (left and right) by 50%.

Ta-da!

This is a topic I know all too well. My last major project, "Me3" was based on this very principle. You can do it in premiere using garbage matts, and chromakeying (green/bluescreen), but honestly, After Effects is your better choice for this. That is what I ended up using in the end. I know that they dont really like links to your own work here, but I really think that in this case, it will help you get a damn good idea. Goto http://JRMorgenProductions.com and click on Our Work, Films.

While watching it, notice the possitions of the figures in most of the shot. Most shots, had each figure on a seperate part of the shot. Shots where figures overlapped, were done with greenscreen compositing. Scenes where figures had to interact, often had stands ins that were digitally replaced. Lastly, the hardest things, were reflections, especially in water. For those, I had to use LOTS of layer masking, invovling complex animated layer masks that just cant be created in premiere. For shots like those, you definately need AE. I dont want to reveal ALL of my secrets here, so if you have any more questions after you watch it, email or im me. Hope this helps.