TchnclFl:
I've only toyed with Fritzing, I have never given it a "proper" workout. As far as I know, it only will output Gerber files (but then again, I have never tried), in addition to its own formats for schematics and such. It won't import or export Eagle (currently - but maybe in the future?).
I would first try a very small and simple schematic, then dump the PCB and see if there is a way to verify what it looks like or that it will be taken by a PCB manufacturer or something (or contact the Fritzing developers or such). I know that some PCB places will take Gerber, but I don't know how the accuracy, etc of the format is in Fritzing.
I am not sure how you could verify or do this properly; maybe you could work with a board company to give you some "free" time or something to allow you to play without committing to a board that will fail (if the format isn't any good)?
Does anyone here have more experience with Fritzing and its PCB capabilities?