It's pretty easy, but takes a couple of weeks. You need to contact the Colorado Department of Education and they can get you the forms you need, or apply online at http://www.cde.state.co.us/cdeprof/Licensure_SubApp.asp. There are 1, 3, and 5 year authorizations. The one year is where you are requested by a school district and only need a high school diploma (very rare instances, think very remote, small towns in need). The three year authorization requires a bachelor's degree and they will want an official copy of your transcripts. The five year authorization is for people with a current teaching license either from Colorado or another state. You also have to get fingerprinted and it takes a few weeks to get those back from the FBI. I used to substitute teach right after I got out of college and back then it was a very lucrative job, and I could work as much or as little as I wanted. Before going through the entire process, if I were you, I would check how much your local school district is paying. Where I used to substitute the pay dropped over 35% when they had budget cuts and I can't imagine working for that little of pay now or back then. If you are good with kids it can be a really fun job. If you have a problem with instilling rules or discipline I would suggest you reconsider. It can be a tough job, but also rewarding. I typically did long term jobs where the regular teacher was out on maternity leave so I was in charge of the entire thing, like a regular teacher would be, doing lesson plans and the whole bit. That also pays a lot more than just day to day subbing. If you are considering teaching as a career, it is a good way to get a feel for how it all works and some of the not so glamorous aspects of the job. I loved the kids I worked with but as far as administration and some of the other aspects of the job, it wasn't for me. In my opinion we have a very flawed educational system that is in serious need of an overhaul, which is why I think homeschooling is becoming so popular.