Do garage doors need to be serviced and if so, what do I have to do and what type of lubrication do you recommend?

I have an older garage door and one of the springs has broken. Can I fix this myself?

The bottom section on my steel garage door is rusting, and it's only a few years old. The rust starts near the floor, and extends upwards about 6". I noticed the jamb weather-stripping has rust on it near the concrete driveway as well. What's causing this?