I think the best way to get a CFI job is by actually hand walking your resume in. All these FBO's get resumes daily (at least mine does). Most go in a file somewhere to be forgotten about.
However, people that walk their resumes in get a serious looking at. I would say when you get time to apply, just go on to airnav.com and look at all the local airports and the FBO's. Then drive around, walking in resumes, HANDING them to the chief pilot (wear something nice, maybe a tie).
I think you have a lot more luck this way then the e-mail/fax thing. Good luck.