celticflyer
Best bet is to do some searches on the site using the search engine provided. A few weeks ago I checked this out as I am also interested in this option. There is much good advice.
It would be useful to know what ratings you have already. Do you intend to become a FI as a full career or do you simply want to instruct on a part time basis (i.e. weekends), alongside a full time job?
I hate sounding pessimistic but you should be aware that the path from PPL to an employed FI is apparently quite difficult at the present due to existing instructors not being taken up by the airlines as much as normal (instructing being the normal step up to the airline jobs).
Good luck,
Fujiflyer