Here is a handy checklist to help you make sure that you've thought through everything and prepared for this most difficult of managerial tasks. (Chapter 6 takes you through the actual firing process in detail). You can also download a free PDF of this checklist from the book's web site at firingatwill.com/checklist.
Before the Termination
Don't fire when angry. Take enough time to make sure that you're not making the decision for emotional reasons.
Choose the appropriate day and time to minimize additional pain. For example, ...