None. It is illegal to employ anyone under 14 years of age, as it is considered child labor. You'll have to stick with babysitting and mowing the neighbor's lawn. Even at age 14, employers are very restricted in hiring, most would rather hire someone older that can drive and work longer hours.
McDonalds
Yes, in the past the Vets Ballpark in Lehi has hired 14year olds to scorekeep baseball over the summer. Its a nice summer job.
Nowhere, unless you do odd jobs yourself, such as babysitting, washing neighbors cars, mowing lawns, etc. Companies in Utah can't hire anyone under 14, but even then prefer not to hire anyone under 16 due to very strict employment laws.
It depends on where you live and what type of job you want. Most jobs do not hire people under the age 18, some jobs do not hire people under the age of 16...
publix
waLMART
craping
Braums I think
There are not many places in Kissimmee, Florida that hire fifteen year olds for jobs. The best place to ask would be the local schools. Jobs that often hire fifteen year olds is babysitting, yard work such as lawn-mowing, and other odds and ends.
Most fast food and retail jobs will hire sixteen-year-olds, provided you're old enough by your state's standard to get a job (which, I believe all states set the legal age at sixteen). Highly technical jobs and jobs requiring experience will not.
No where, you can't hire someone that young in Utah. You will have to come up with creative ways to earn money such as babysitting or lawn mowing.
Jobs in Oklahoma for a 12 year old would be found around your neighborhood. Most companies will not hire a 12 year old but your neighbors might hire you to do small tasks like walking pets or mowing grass.