The Mayo Clinic’s information for NS is exceptionally well written. I found it really helpful to read it all in ‘normal’ english as opposed to all the scientific documents we were given. I sent this link to our friends and family so they could easily understand what NS entails.
http://www.mayoclinic.com/health/noonan-syndrome/DS00857
One quick note - the information is slightly out of date as they list only 2 genes as responsible for NS whereas there are currently four but the documents are so well written that for us, and our families, this isn’t a factor.