Hello, There is a list of C++ XMLRPC implementations in Wikipedia:
I wonder that people use which of these libraries most. Do you have experience with these libraries?
I think that xmlrpc++ is what you're looking for. Though I can't give objective comparison to every library listed here, I must say that's it's extremely versatile, well-written and somewhat easy to get used to.
Well, it actually some kind of lacks in documentation, but this is also subjective (hate this doxygenized way of presenting information).
Added : ulxmlrpcpp also (never used it, just looked through documentation) seems fine and well-designed.
I've used gSOAP in the past. I found it pretty nice to work with. It's fairly mature and runs on a variety of platforms. I thought the documentation, along with examples to be sufficient. We used it on a project that needed to communicate with ASP.NET web services from a Linux environment.