I would write a letter and hand deliver it, however I think this issue is very important to many.
As one of the owners of WestPA.net we have been directly involved in checking computers where the owner was a potential victim of a fraud.
This fraud involves the victim receiving a call from someone purporting to represent Microsoft or McAfee, or sometimes a different anti virus company.
The caller tells the victim that they have become aware that the victims computer has some virus, or a malfunction in their computer that requires immediate attention. The victim is then prompted to permit the caller to have remote access to the computer so they can "fix" the problem.
The problem is then generated by the caller during the remote session. The victim is then told that it will cost some amount - typically $129 or $229 to fix. The victim is then asked to provide their credit card number which is then used online for purchases.
It is important that your readers are aware of this fraud. The best advice is to hang up. If your computer has issues call someone local and have it fixed. NEVER grant remote access to anyone who calls you out of the blue.
If anyone has been victimized by this fraud they should immediately contact their bank and credit card companies and make sure that their accounts are locked. Obtain new cards, and new account numbers, and change their passwords. The moment access was granted the caller obtained every bit of critical information from their computer.