Is there an alternative to Adobe Fireworks?
Solution 1:
Pencil Project (Download Link)
Despite the similar names this is different from Pencil.
The Pencil Project's unique mission is to build a free and opensource tool for making diagrams and GUI prototyping that everyone can use.
Solution 2:
Pencil (Click to install)
While mainly made for animation purpose it can be used for drawing and supports bitmap and vector graphics .
Pencil is an animation/drawing software for Mac OS X, Windows, and Linux. It lets you create traditional hand-drawn animation (cartoon) using both bitmap and vector graphics. Pencil is free and open source.