First of all you need to get the football leaders coaching badge, this is easy to get and it enables you to work with children. You can find out dates for these courses here
http://www.welshfootballtrust.org.uk/coaching. I am hoping to do the same thing as you & I already have the leaders badge, your next move should be to talk to some childrens football clubs and ask if you can help volunteer coaching, this will give you good experience.
I am looking to go to Glamorgan University in September to do a football coaching foundation degree, this will give you the opportunity to get a lot of the badges and the university will fund you to do the courses. They will also send you out on work experience to gain further hands on experience.
This is the best sort of route into football that I could find, hope it helps. There are other football degrees around the UK, the best was in Liverpool which I had got accepted onto however with the current cuts they have now decided to drop the course so I will be doing it in Glamorgan.