Royalty-free! Royalty-free! Royalty-free!
I suppose it was due to the fact that in the early drafts of WS-Security, we made you sign a license to implement the spec, but we have taken a lot of flack about what our intentions are around royalties and our Web service specifications. The WS-Security license agreement was only done to make sure people understood this was an early draft, things were changing, and they had better be ready to modify any work that was being done. We did follow through with what we were saying all along: once we were pretty baked, we went to Oasis for ratification and of course WS-Security is now ratified and royalty-free.
But just so there is no question about what our intentions are for all the other specs, here is a public pronouncement around 26 Web service specifications.
For information about all these specs, check out the Specification Page on the MSDN Web Services Developer Center.