I've played with time-lapse photography using my father in law's Canon Rebel, using a USB cable, gphoto2 and an Ubuntu laptop. I want to create similar videos using my own A590 IS, but it cannot be controlled from a USB cable. The only solution I found on the web is firmware enhancement using CHDK.
How safe is CHDK? Is there really a way back? Are versions above 1.xx mature?
Update: Thanks for all the advice. I've successfully installed CHDK on my SD card and shot my first time-lapse using my A590. Works great!
Another Update: Installed on my 550D. Works without problems, and I can choose not to load CHDK at boot time (by long-pressing a button).