It's not illegal to postdate a check, unless you're attempting to commit fraud.
You can land in legal trouble if you intentionally postdate a check knowing there will be no money in your account or the account will be closed by the check's date.
Your request should include the recipient's name, your account and check numbers, and the check's amount.
Check recipients can either decide to accept or not accept a post-dated check.
On 15/01/2012, the cheque will be no longer a post-dated cheque, but becomes a current dated cheque.