There are a lot of "how to" resources online for taking photos of fireworks which I have bookmarked for reference. For example:
Tips & Tricks for Photographing Fireworks (from Weekly Photography Tips)
How to Shoot Fireworks (from Scott Kelby's Blog)
The family vacation to visit family and friends in southwestern Ontario started early enough so that we could take in the Canada Day celebrations in Sarnia. I was able to shoot the fireworks at night, though it was hit and miss, mostly because I was located downwind. The wind was fairly high that night, so the fireworks blew around, and with long exposures, this was quite noticeable. The other thing I should have taken into account was the smoke from the fireworks. The smoke is evident in the photos I took and also reflected the light from the fireworks, making for some odd abstracts. Below are several of the better photos from the fireworks display.