Unfortunately, in a few years time it may become a reality that in order to run 'Web Services' or other technologies, you will have to pay a comission to Microsoft. Certainly judging by their movements recently, and from some 'sources' I've spoken to, this could become reality.
However, at the moment you've nothing to worry about as long as you're not redistributing core MS components.
However, at the moment you've nothing to worry about as long as you're not redistributing core MS components.