After Effects 7 masking

[ZephyrStar]

What Zarx said


It's much easier to export it as a .TGA sequence, (32 bit!) load those up in photoshop's file browser so you can see all your frames, and then open and mask each frame. You should have one single layer, and you can erase around your character using lasso/quickmask/etc. and delete that so all you have is your character on the transparent background, then save it and move on. Then when you load this back up into AE/Premiere, select the first frame and make sure to tell the program you want to load it as "targa sequence"

...I need to check out CS3 also...

although, if you want to do it completely in AE,
1) cut your clip
2) bring into AE
3) make comp that matches clip resolution/framerate/length/etc
4) put something under the clip so you can see through it once you start masking
5) add a new mask to the clip itself (right click on it > mask > new)
6) use the pen tool/point tool to add and move points
7) key the mask shape on every single frame
8) for duplicate frames, move playhead forward and just check the mask shape key to the left
9) profit?