Identify yourself in the body of the letter. Sign your letter.
Signatures are extremely important as well as courteous.
If you've requested information or expect a reply, you must identify yourself and give your addressee a way to contact you. If possible, write a simple signature file with your name, your title, your email address, and your web page location if you have one. But don't go overboard with it. Words written entirely in capital letters are hard to read and, in the computer world, only signify force. All-caps does not add emphasis to your words, and it most often causes people to stop reading.