Being fortunate to get over a lot of the early challenges of creating a company (building the right product, getting customers, sales, raising money, getting the core developers) we are now tasked with scaling a development team.
Almost every CTO I have spoken to in the meetups that I host http://www.meetup.com/Toronto-CTO-Group/ implement some form of Agile. A very quick look on Wikipedia will list almost 100 different development methodologies (https://en.wikipedia.org/wiki/Software_development_process#Software_development_models). Most are iterations of one core style but there are still a lot.
I found these two articles helpful when I was digging more into this process. We run Agile here at viafoura.