Across the nation, many states have either legislated (or are currently in the process of legislating) mandatory CS instruction, so this is a fantastic time to find a job in CS education. In general, there are two paths into the classroom (at least in the public schools).
The first way is to go back to school and get a traditional education degree. There are many graduate degree options available in every state to accomplish this. The degree program will also typically walk you through the process of getting your teaching license within your state (though details for licensure in ever state is but a few search terms away!)
The second path is often called alternate route (though some states may have different names for it). Typically, an alternate route position is created by working directly with a school that would like to hire you even though you have no license, and then working with the state through them. There may be a background check needed before you are even allowed to apply. Again, your students should search for "alternate route, StateName" to get a sense of the procedure and requirements for their target state.
Tell them to be prepared for a very steep learning curve when they enter the classroom as a teacher. While attrition rates are nowhere near the fabled 50%, they are still quite high, and there are many, many reasons for it.
The first several years are physically and emotionally punishing. In my experience (at three schools so far), getting started at a new school or in a new position requires an absolutely breathtaking amount of work just to survive for a few years. During my first three years as a teacher, it was not unusual for me to be in my school building from 7:30am until 11pm, only to report back the next morning and do the same thing all over again. Weekends were for planning, and vacations were for catching up on mountains of grading.
Along with all of that work and exhaustion also comes the emotional roller-coaster. The highs are exhilarating and the lows can be quite dark. If you can make it through the first couple of years, it really does get easier, and you can switch out of "fight or flight" and really start honing your craft. That is when the magic really starts :)
Tell them to join professional associations (like the CSTA). And, no matter how much they need a break, go to at least one conference during their first year. Those conferences will bring them a million ideas, give them a chance to meet other teachers, and also remind them of how very sweet that light at the end of the tunnel is.
And tell them to find some place they can go to with questions to help them deal with all of the bumps and pains along the way. Perhaps even... this very site? ;-)
1 - My knowledge base is primarily in the state of New Jersey, but I have reason to believe that many states work very similarly.