not as a hobby, but i sometimes edit for films and documentaries.
we use Final Cut Pro 7. its pretty easy to learn, actually.
when we were being taught editing, they'd make us practice by making movie trailers like -- make the film Apocalypse Now a comedy or make Legally Blonde a legit courtroom drama.
yeeeaars back, i was just using iMovie, which if you're familiar with, and want a more advanced program, get Final Cut Pro X.