GerbV Portable
A Free/Open Source Gerber (RS-274X) Viewer in PortableApps.com format
GerbV Portable is a viewer for Gerber RS-274X files, Excellon drill files, and CSV pick-and-place files packed as a portable app so you can do your CAD design on the go. It has all the same features as GerbV, plus, it leaves no personal information behind on the machine you run it on, so you can take it with you wherever you go.
Learn more about GerbV http://gerbv.geda-project.org