Nick,
As mentioned previously, cabin crew training is about 4-5 weeks and sometimes a little less and others a little more. I did a quick EP training course with a major airline a few years back and it was 12 days solid. The airline I work for now took three weeks for ground school and then a couple of weeks of line training, before being passed to fly. As solo flight attendants you really need to know your stuff when the proverbial hits the fan!
As for checkin - I knew nothing about airline ops as far as reservations etc and I learnt what I need to get by, in about three days. It was a constant learning curve for the next three months, trying to get my head around a completely foreign booking system, along with DG's and the airline requirements for seating etc.
Operations side of things was a completely different kettle of fish! You really have to have your mind switched on and be able to multi task every moment of your shift. I guess it took a month of working every situation before I became comfortable with the position. Even after all that.. you get one day that throws a spanner in the works and you really earn your money! Just ask Adam P!!!!
Hope this helps.
David.M.