yes.
if you have a static foreground with moving background
use png or tiff files created in photoshop.
use layers to create transparency.
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if you want a moving foreground thats a whole different can of worms.
you need to have some real experience doing this in post-production - before beginning to do this type of thing.
keying ( green screen or whatever ) - is not as simple as it first appears - particularily with digital video sources.