How to put a fragment of a video on a background?

[RcK17]

Sorry if My question is answered already, but I searched and couldn't find it out. Maybe I simply don't know how to call this action in English...

How to put a fragment of a video on a background? For example, if I have a video of a moving crowd and a video myself walking, how do I put myself into the crowd? I know this is done somehow by using a background of one bright color, like green or blue to make the cutting easier... but with which software?

Thanks,
Vykintas

[thecoalman]

Tyr Ulead Video Studio for a cheaper alternative, other than that any of the major editors have that feature.

http://en.wikipedia.org/wiki/Colour_Separation_Overlay