How would I make a time lapse video over a two month period?

You would need to get an SLR with a mains power unit (often an optional accessory, you usually only get a battery charger) and that can take a timed controller. I have a Ricoh GR that has a timed facility, but it is a fixed focal length lens. An SLR would give you more versatility. Canon cameras come with remote software so you could run it from a pc and save to the hard drive, wouldn't think that leaving a computer on for 2 months solid would do it much good though. If you are shooting something outside then bear in mind that at night time you will need a vastly difference wb and shutter duration than in daytime, at nightime the required exposure duration may also be longer than a minute. I would vote for a higher end canon, such as a 40D, 50D or 5D, as these can accept canons timed remote controller.

you could use a canon XL1 or 2 you can record at intervals of 30 sec., 60 sec., 5 min., 10 min. and recording times of 15 frames, 30 frames, 45 frames, 60 frames. if you wanted to make a video. on long play you can get 85 minutes out of a tape, not sure if you can record it directly to a hdd on time lapse never done it for that length of time. but thats half a second (15 frames) every minute for 2 months, I think night time is going to be a problem if its very dark Good luck RR