Eagle CAD
How to get Gerber files out of EagleCAD
You cant just send eaglecad files...you need to generate drill/rs-274x data. In the latest version of EagleCAD i believe you dont need to run the drillcfg.ulp anymore.
SparkFun has another tutorial for their PCB service which has a script for increasing the silkscreen width, which may be useful with other services
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