If you are on Windows Vista and unable to install MySQL as a service with the following error message:
"Could not connect to the Service Control Manager"
it's because you are not running the "MySQL System Tray Monitor" as a administrator. I am too lazy to wipe up the Windows Vista Home Premium and install a more complete Vista version, and sometimes I spend time with these problems that happen due to the User Access Control.
By the way, the "Service Control Manager" is the Windows Manager for all OS services, it is not something that is part of MySQL as one may think.