Check
www.inyourpocket.com for information about hiring tour guides within each of these cities. Or better yet, when you get to each of these three magnificent places, buy the In Your Pocket guide (they run the local equivalent of about $2-3 US, and are worth their weight in gold - wait til you arrive to get the latest copy) at the nearest newstand, and have fun exploring the city on your own. You'll find all the info you need, and half the fun of traveling is the things you discover when you are ... geographically challenged.
Feel free to ask any specific questions you might have here, many of us have traveled in and love eastern Europe and are full of tips, recommendations and opinions about the region.