A little discouraged

I know that this is a difficult time for people to obtain jobs, especially in particular fields. I have been working as a substitute teacher for my local school district the last year and a half, graduated with my teaching degree in May of 2011. I currently have applications filed with three districts close to where I live, which allows me to send a letter of interest when I see an opening I would like to be considered for, and nothing. On several occasions I have been sent an e mail from a principal saying that they will be reviewing applications for a certain teaching position and if interested to let them know. I respond to the e mail stating my interest and then never hear. It has been the same on the few interviews I have been on, we like you, we think you are great, but then someone else gets offered the position. I know for the charter school I was lacking the Masters degree that they "preferred." Otherwise I am at a loss. There are quite a few teachers that request me as their go to for a substitute. After a long term substitute job in which I took on all the duties of a teacher, to include planning, I was told I would make a great teacher by many of my colleagues I had worked with during the time at this school, a couple of them even wrote me letters of recommendation, so why is it I can't manage to land a job? I know the job market is tough and that there are many teachers, especially ones who have several years of classroom experience out there, but how does one get long term classroom experience when they aren't even allowed out of the starting gate?