SPAM!

I've been asking for this since the iphones inception and haven't see it anywhere. My MacBook catches all my junk mail, but my iPhone gets every dang shred of it. I would be happy enough just having a way to set up a spam filter on my iPhone, but what I would REALLY like is for my iPhone to actually sync itself with my MacBook mail which would not only make the spam filter active, but would update itself automatically.