It seems you really can do just about anything on an iPhone ... I'm trying out an app called TimeLapse (currently £1.19) which basically takes a series of photos and saves them to the camera roll. You need to copy the images to your computer to actually compile a video from the photos, but most operating systems now come with basic 'movie' software that will do this quite simply.

The images captured (on the iPhone 3Gs) were 1600x1200 and about 400kb in size, there are about 200 images in the movie below ...

You can fully customise the start time, the end time, the time between photos and make it finish after a set number of photo's have been taken. The app also allows for 'Dark Display' which turns off the screen to stop glare and save power - although I think you'd need to keep the power cable in on this one.

A couple of things that you should note:

• I wouldn't want to do this sort of thing too often, the iPhone is an expensive piece of kit and leaving it on a hot window all day could be asking for trouble.
• The built in camera probably won't thank you for shooting into direct sunlight.
• If you are popular, you are going to have trouble answering calls.
• Use aeroplane mode to avoid movement of the phone.
• You will probably want some kind of stand, dock or holder.
• The 3Gs uses autofocus on every shot and will compensate lighting conditions - this is not ideal for timelapse.

Oh, and as an extra bonus, I've also used the software to take a time delayed group photo - with me in it of course.

Check out my TimeLapse using an SLR camera:

Christmas Tree TimeLapse

Train Track TimeLapse (HD)