For Prague we can HIGHLY recommend Sarka...her website is HERE. Not only was she extremely knowledgeable, she was also very personable and friendly. She went out of her way to help us find a doctor when Art was struck by shingles, and also helped us file a police report when his pocket was picked. She also worked with us, helping us plan our itinerary, including day trips outside of the city.
Thanks so much for your excellent recommendation. Another person had recommended her guiding services, as well. I feel confident we would have a great experience touring with her.