Google Analytics Form Tracking

I have a form hosted by a third party that is iframed into our site, the form is written in .aspx I need to have a Google Analytics script written that will pass specific form fields to GA no personal details will be passed just three or four generic form fields that we need to capture. The third party host of the form is okay with us adding java script into the form page to accommodate this but it needs to pass a security review at completion. It will require you to asses the current form, produce the script to be added to the page and provide instructions on how to set it up in GA.