OK..I don't remember my exact settings... because I will change them while shooting based on what result I'm getting. But the rule of thumb is that you want to see the light.... and keep the dark background. So even though it's dark outside, you use bright daytime settings!! I have full manual control with my camera. So, I start with a tripod...with a remote shutter release. I usually set my camera at f/12 and shutter speed at about 3 seconds. I also use ISO of 200. The idea is you want to keep the shutter open long enough to get the 'trails' of the fireworks. I've had decent handheld results with f/11 shutter at 5/100sec, the trails aren't as pretty... but the pics are not bad.
The same concept applies to shooting pics of the moon. The moon is reflecting sunlight, so you figure your settings for daylight, even though it seems opposite of what you would think you'd do.
Mind you...this was not taken with a tripod, cause I was practicing..so it's not nearly as sharp as it should be
I have learned TONS just by reading the photography boards here onthe DIS.... thats where I learned about the moon shotsand I got some GREAT advice about the FW photos there too! Check them out if you get a chance
Paula