The 6 month from non-diving to divinginstructor are no good if you try to do work somewhere else they won't hire you !
If you try to get a diving sertification build it up slowly and get good education. see :
http://diveproinfo.proboards25.com/
Read on this boards i read a lot off shit in respect to these courses , the prices they give or the equipment are also on the high side.
If you want to do this just start diving and build it up from there.
Whatever you do good luck,
Frank