Dear <Boss's name>,
It is time for me to move on in my career. Another firm made
an exceptional offer and I accepted as I feel it is in my best
long-term interests.
I will wrap up most of my projects and administrative responsibilities
and will turn over my notes and clean out my desk by 11 am on
<insert date>.
I will not entertain a counteroffer, as this company provides
an opportunity for me that <current employer's name>cannot
provide.
I want to thank you for the opportunity to working with you
and I hope I can leave with your good wishes. I wish you and the
staff success.
Sincerely,