I, Mike, have started CFI training. I have the FOI and CFI-A Knowledge tests done. Now just need to find time to get with an Instructor for the oral and Practical parts. In the mean time I've been working on collecting anything that I might need for those tests. I Thought about buy copies of books like the Airplane Flying Hand Book, Aviation Weather, Aviation Weather Services, etc. but all of those are FAA publications and freely available from the FAA's website as PDF documents.
As most of these publication can be updated at any time, printed books costing $30+ each, that may be outdated when you get them, doesn't make since in this digital age. The AIM is updated every 6 months and FARs are updated so often the FAA doesn't even bother with a PDF they say just use the online database. Now I just need to decide on an E-Reader type device that I can take with me to the oral exam to access the PDFs from the FAA. I'm gonna call my local FSDO and ask if my laptop is acceptable before I decide to drop ~$200 on an E-Reader. All the books I want to get total to around $250.
Well anyway here is a link to all the junk I've collected: http://media.burnclouds.net/cfi/
Update 1: I called the FSDO and the examiner said a laptop (no internet) would be fine. "That is what we use here in the FSDO, laptops, book are too expensive and mostly outdated by the time you get them anyway." So, The laptop goes to the oral too! :-)