In Fireworks CS4, efforts have been made for a greater integration with other apps of the Creative Suite (Photoshop, Illustrator, etc.) and for embracing leading technologies for the future like Thermo, Flex or AIR. The diagram Figure 1 represents the different links of Fireworks with applications or technologies.

Figure 1: Fireworks integration with other apps
Fireworks CS4 shares now a common interface with Flash, Photoshop and Illustrator and works with tabs.
The new UI is a customizable workspace, you can organize, split the screen into 2 or 4 views.

Figure 2: User Interface
With Fireworks CS4 Smart Guides, a pink dotted line automatically appears as you drag to let you know when items are aligned. Read tutorial.

Figure 1: Smart Guides and Tooltips
2 new tools are available to make measurements easy: tooltips and the Measure Auto shape. Read tutorial

Figure 2: Measurements
The new Take Screenshot command enables you to take screen shots not only from Fireworks but of any other applications opened. Read tutorial

Figure 3: Take Screenshot
You can now wrap text around shapes through the Attach in path feature. Read tutorial

Figure 4: Text Wrapping
In Fireworks CS4, create AIR packages along with AIR mouse events. You can preview and create a prototype as an AIR application. Read tutorial

Figure 5: Create AIR package
Fireworks CS4 has the ability to open an Illustrator file that contains Artboards and convert them to Pages. Read tutorial
This command makes it easy to export your mockups and wireframes into a slick slideshow geared for giving quick presentations to clients or colleagues. Read tutorial

Figure 7: Demo Current Document
In Fireworks CS4, export a clickable prototype/wireframe as an interactive Acrobat PDF. No need to send around a folder of HTML files and images or post them on a server for review. Easily collect comments from reviewers using a single PDF document.
For more information about this feature, read Jim Babbage's article: Creating an interactive PDF file from a multipage document in Fireworks CS4

Figure 8: PDF Export feature