It should be in your Applications folder. It has to be said, though, that iMovie is more a tool for editing video footage to produce a finished movie with audio and visual effects, that is then exported to dvd or as a movie file, rather than the video equivalent of iPhoto.
True . . . and iDvD (also part of the iLife suite ) works pretty well for the latter.
I probably should have been more lengthy (and helpful) with my post, didn't want to take the time at that point.
My main reason for pointing the OP at iMovie wasn't so much iMovie's strengths but my experience in doing exactly what he has been doing.
For years I used iPhoto (then Aperture) as a repository for both photos and videos. As a result my libraries began to swell (63gb) on my main Aperture Library before I decided to do something about it.
Now, I have broken my video files out into their own Aperture libraries and am in the process of importing them into iMove and Final Cut Express (where they probably should have been all along).
As a result, my main Aperture library is now a more manageable 25gb.
