Well, you CAN have less grain, but then you need to shoot at lower ISO, which means the contrasts will be lowered and the exposure time will increse ALOT. But my camera cannot get over 30 seconds on it's own. Then you have to use a timer or a remote (or whatever they are called on cameras). And I don't have that. :P

It's the same technique as capturing long tail lights when shooting a road at night.

Hmm, not really.. Experiment! Just try shit out. Read the manual, search for photography tutorials etc.