Get notifications on security alerts for Windows & SQL Server environment

Got an interesting question in SSP about the SQL Server security patches that are released by Microsoft:

1) How often does Microsoft come out with security related patches for the database ?

2) Is there a URL where we can sign up to get notified about these patches if and when they are released ?

Here is the response, there is no specified timeframe to say within x months you there will be a security update patch, but its worth check every month for such bulletin information from MSSecurity site. Also you have information over there about how to get notifications for such updates.