I've never kept it in the freezer more than a month or so, myself. I think that it would freezer burn after a while, due to the air spaces between the grains. How that would effect it I don't know though.
Yeah we stick it in a freezer bag and freeze it. I guess the longest it's been in there is 2-3 months. Tastes just as good as freshly cooked... in fact even maybe a bit nicer? Just pour a kettle of boiling water over it slowly and it's ready to eat.
Oh, by the way, I'm sure most of you know this, but there's something which grows on cooked rice very quickly once it is cooked that produces a really bad toxin, so don't store cooked rice in the refrigerator.