This is the one i used about a month ago
LINE MANAGERS NAME
OFFICE ADDRESS
OFFICE ADDRESS
OFFICE ADDRESS
OFFICE ADDRESS
OFFICE ADDRESS
OFFICE ADDRESS
DATE
Dear BOSS'S NAME
Please accept this as formal notice of my resignation from the position of ???????????? with effect from ??????????
I realise that my contract of employment requires me to work until ?????????????, however I'd be grateful to be released on 26/03/2008, and will assume that this is acceptable unless you inform me to the contrary.
While I believe that I am moving for good reasons, I am sorry to leave, and I thank you for your support during my time with the company, which I have found enjoyable and fulfilling.
Yours sincerely
NAME
Signed_______________________