The XsdToClasses tools, which I’ve been using for most of my software development for many years, has been published as open source at Google Code. The license is the GPL V3; note that since the XsdToClasses tool is a code generator, the tool itself is GPL, but the code it generates is most definitely not; the output from the program can be under any license you like.
I use this tool so much, and it has saved me many hours of development time over many years. May it serve you well also.
Maybe check out the libraries from JMT (www.jet-messaging.com), especially if you are faced with global Schemas from (Open Travel, ISO, IATA, HL7…)…