For the consumer and smaller business, security is an after-thought (if a thought at all until the bite of identity theft or stole credit card numbers hits). TechRepublic has 10 no-charge apps that you might want to start offering your clients.
In similar news, Bits du Jour has DefenseWall Host Intrusion Prevention System for sale.
There are ways to make revenue on Software as a provided or managed service. What are you currently doing to ease the pain of PC problems for your customer base - and make a dollar?
Even if your clients signed up for other back-up services, like thebox.net or myfabrik.com, a reminder service to update Microsoft, update their anti-virus, or to back-up important data would be a way to add value, look like the expert, and keep your name in front of your clients regularly.