Joel Spolsky gives a good summary here: http://www.brightjourney.com/q/working-company-intellectual-property-rights-stuff-spare-time http://www.brightjourney.c

Joel Spolsky gives a good summary here: http://www.brightjourney.com/q/working-company-intellectual-property-rights-stuff-spare-time http://www.brightjourney.com/q/working-company-intellectual-... The key phrase seems to be this one: "These state legislatures usually passed laws that said something like this: Anything you do on your own time, with your own equipment, that is not related to your employer's line of work is yours, even if the contract you signed says otherwise." (emphasis mine) This suggests doing external work on company equipment might be a bad idea.