$400 voucher is being advertised but Westfield Chatswood is throwing in an extra $100 and making it $500. Today and tomorrow only I was told.
Mod: Note that the OP is associated with JB Hi-Fi and posted the deal for Westfield Chatswood only, however comments indicate that it's available Australia wide. Check with your local store. Deal updated.
Wow. The kickback they get from Telstra must be insane.