inquiry about the methods for gene knockout in bacteria - (Mar/13/2012 )

Hi I want to knockout a gene in a bacteria.

I am a new starter. Would you please give a general picture about how many methods I can choose, so that I can read more about them and choose a suitable one? I get confused when I read papers for their different methods, so I want to get a big picture first.

Thanks a lot! And look forward for your response!

Its just flanking region of gene you have to choose. goal is to add resistant marker replacing middle portion of flank, then later removing resistant marker too.
- thats all you have mutant.