Mine sometimes smells funny too. I think I might have the lipase problem, which makes it so your milk doesn't last as long as it otherwise should. So I've started scalding the milk before freezing now and hopefully that will help. The signs of excess lipase are that it has a soapy or metallic taste after a while. I think mine has a soapy aftertaste. I've done experiments, and mine seems to last about 3 days in the fridge and somewhere from 2-4 weeks in the freezer (unscalded) before it smells/tastes funny.
Here's a link to info about excess lipase in case you think it might be that:
http://www.kellymom.com/bf/pumping/l...essedmilk.html