Not all of you may know this, but I found this free open source gerber
viewer that seems to work nice.
From the overview:
-Gerbv is a viewer for Gerber RS-274X files, Excellon drill files, and CSV
-Gerbv is a native Linux application, and it runs on many common unix
-Gerbv is free/ open-source software.
-You may download the source code from this page.
-The core functionality of gerbv is located in a separate library
(libgerbv), allowing developers to include Gerber
parsing/editing/exporting/rendering into other programs. Documentation for
libgerbv is here.
-Gerbv is one of the utilities affiliated with the gEDA project, an umbrella
organization dedicated to producing free software tools for electronic
-The latest official gerbv release is version 2.3.0, released on 2009-07-11.