This is an official notice of employee termination, usually given when there is the potential for later legal action by the terminated employee.
Pursuant to the terms of your Employment Agreement, you are hereby given <amount of notice> notice that your employment with this company is being terminated. The effective date of your termination will be <date>.
After careful consideration, the decision to terminate your employment was reached on the basis of <reason>.
If you wish to discuss compensation and/or severance pay, references or any other matters, please contact me at your earliest convenience. While it is always difficult and unfortunate when we have to sever a working relationship, I hope this transition will go as smoothly as possible.
Good luck in your future endeavors.