you sure can. just don't freeze the cow!!!
I'm not crazy about it for drinking straight, but it's fine in tea or coffee. What it really won't do properly is make yogourt or quark. The ultra high temperatures that it is treated at apparently do something to the milk protein, so it won't form curds properly.Ah, long life milk....
It's ok to cook with, but I can't drink it like "standard" milk.
Maybe that's just me...
And yes, freezing milk is fine