Susanb
Have you thought about doing some voluntary work in a school near to you to see first hand what you think of it. I have good and bad experience of the job. My first school was excellent and I loved it. My current school is poor and it isn't as much fun. I can tell you much more about the pros and cons IME later if it is relevant to the age you will be considering.
In terms of fitting it around children I think it is better than many jobs but I still have childcare. I work part time and my daughter goes to nursery 2 days a week and my MILs one day a week, from 7:45am to about 4pm. If I have parent's evenings or meetings I have to arrange additional child care - some my DH can do but I have to get DD home and back to school quickly - different town - so it is a rush. I have about 8 parent's evenings a year and those days I get home at about 8:30pm (a long day). Then you have meetings each week too, some may be before school so you need child care to cover this if necessary. In the school holidays you will probably still have to pay for your child care - most nurseries charge full - to keep your place open, which means you are paying for up to 13 weeks you may not use. This summer I plan to send DD to nursery one day a week, for consistency for her and so I can work on planning, etc. without distractions.
If you have a child at school try to find a school in the same area so that your holidays match, otherwise you will have time off whilst the are at school and vice versa. Also, you may need to arrange how you will get them to school and picked up each day, as you will not be available at that time. Unfortunately not many state schools offer supervised morning and after school clubs - they don't do it much now as the school is supposed to pay teachr's for that time and they often don't want to!!!
In the evenings you will have work to do so don't expect to finish at 3:30. I normally have at least 1-2 hours a night of marking or planning, or reports, etc. to do after DD goes to bed.
On the good side though - I am home to play with DD in the early evening and can work later on.
Let us know more of your ideas - age you want to teach, subject, location, type of school, etc. and I may be able to give you more info.
Good luck.