http://www.scribus.net/

Scribus is an Open Source program that brings award-winning professional
page layout to Linux/UNIX, Mac OS X, OS/2 Warp 4/eComStation and Windows
desktops with a combination of "press-ready" output and new approaches to
page layout. Underneath the modern and user friendly interface, Scribus
supports professional publishing features, such as CMYK color, separations,
Spot Colors, ICC color management and versatile PDF creation.