Cooking Schools In Chiang Mai

Taking a cooking class is an incredibly popular activity in Chiang Mai.  Every tourist office (where you can book tickets, excursions, classes, etc) has advertisements for cooking schools, and there are probably 20 cooking schools in town.  

If you're looking for a great class, skip the tourist offices and contact schools directly. They are easy to find on Google, and a lot of them distribute brochures to guest houses and restaurants around the city.
 Ask them who will be teaching the class and the experience they have, how many students are typically in the class, and how many different recipes you'll be making.  Steer clear of classes with more than about 5 students.  I've seen HUGE classes go to the markets, and it doesn't look like you learn much of anything.

The girl I was meeting suggested May Kaidee's, because she's vegetarian and loves the restaurant (there are branches in Chiang Mai and Bangkok). The class was a little bit more expensive than some of the others, but we got to make 12 different dishes, and because there were only 3 people in the class, we could all ask a bunch of questions and have them answered. I enjoyed the class, but unfortunately don't have anything to compare it to.
If I were going to take another class, I would seriously consider A Lot of Thai because I've heard great things about it.