There is no built-in interval recording on the GH1. The only way to really do it is by remote controlling the shutter with an intervalometer. As this is how time-lapse is performed in still photography on all cameras (activating the shutter), I think you're safe in going this route. Sure, multiple shutter firings will eventually wear it out, but this is the only way it's done.
You do have one alternative: shoot in Movie Mode at a slow shutter speed, then speed it up in post. But this will run down the battery MUCH faster, record hours of unnecessary footage, require a large capacity SD card, and will only record 1280x720 images, as opposed to a series of 12 megapixel still images that have a higher dynamic range.
It's not "bad" for the shutter, but obviously shutters are designed for a limited number of actuations, and in time lapse, you use a number of those actuations up. Well that's what a warranty is for, right? Get out and get firing!
nice video Ianb.......my question is once you use intervalometer do you still have to lower the shutter speed manually or does it automatic does it for you