I also posted this question on the Swedish 140-klubben's message board, and the answer was simpler than I thought. As I write this, I have taken out both windows. Basically, you sit down one the edge of the back seat, put your hand on the inside of the window and start pushing. Probably not something you want to ask your 100 pound wife to do, but... I found it a bit easier if I started pushing on the front vertical side of the window, near the gasket. Use your other hand (fingertips) to help the rubber start lifting off from the sheet metal lip. Once it's started loosing, you can greatly reduce the force and it comes off rather easily. Can't say much (yet) about reinstalling, though.

Kåre
Oh yeah, and be prepared to find some rust at the bottom, under the gasket.