There are two major types of lessons: through a school or privately. Many music stores or schools will offer instrument-specific lessons. A quick online search can direct you to local music schools.
There is also the option of finding private lessons through people that already know how to play the ukulele. Again, the internet will help you with this endeavor. Perform a quick Facebook search to see if there are any ukulele or even just music groups in your area. Online classifieds are also a great source to finding private or semi-private classes.
If you live in a very small town without a music school or any opportunity for private lessons, then a final option may be online videos. YouTube will have a large selection of tutorial videos where you can try to follow along and learn yourself.