We've been doing this for a quite a while now and it works fine. We buy non-fat (skim) milk in half-gallon containers, transfer it to clean quart containers, date and freeze it. Using the oldest first, it's normally used within 4-6 weeks of purchase and we don't notice any deterioration in flavor.
Caveats:
1. Wash and rinse freezing containers thoroughly.
2. Leave about an inch of air space in the container to allow for expansion upon freezing.
3. While frozen, the milk will have a yellowish color. This is normal and disappears once it has thawed.
4. In our refrigerator it takes about 48 hours for frozen milk to thaw so plan ahead.