That’s right — according to my mail reader (Apple Mail 3.1), I have 4 billion, 294 million, 966 thousand and 24 messages in my mailbox. Only 2 unread though, thankfully.
Weird. It’s been this way since I upgraded to Leopard.
I have been experiencing a similar issue – message dates that should be January 2007 (or earlier) appear in my mail window as January (etc.) 2008. Thanks goodness there’s nothing futuristic yet – that might make me a bit nervous!