J.H.
Kay's Swim School is located in the North Valley off Fourth Street and they offer toddler classes. I haven't enrolled my daughter, yet, but they've been there since 1974 so I think it's safe to assume that it is a good school. http://www.kaysallswimschool.com/classes.html
Preschool: my 4 year old goes to Albuquerque Preschool Cooperative and we love it! They have a 2-3 year old program that has a limit of 10 children and has 2 teachers plus a parent aide. All parents must aide at the school one day month, which is great because you get to know and participate with the teachers, the other children, and the program. Parents must also select a committee to work on, such as fundraising or maintenance. The program schedule is AM or PM on Tue-Thurs. or Mon, Wed, Fri. The fees are very reasonable, too, because of parent participation at the school. They are in the North Valley off Candelaria. It may not feel convenient since you're in the Heights, but it may be worth considering. They're registering now. The phone number is ###-###-####.