I am using Fireworks to design.
take a look at these tutorials:
I answered a similar question here : Export Illustrator CS4 File Web HTML/CSS Etc
There are a variety of ways to go about doing it, and depending on the way you want the final site to appear, there are even some automated tools to help. My best suggestion it just to hit up google for "Slice Fireworks." When I did that, I got just about all the results I needed on the first page. Here are a couple:
- Learn How to slice your designs in Fireworks CS3
- Create a Slice Template with Fireworks
- Fireworks Slice Tutorials