Information
Dave Golber's write-up How to Make a Macedonian Tapan is the classic resource. I learned from it and you should probably read it, even if you don't plan to make a tupan.
Dennis Waring, Making Drums, Sterling, 2006 (ISBN 978-1-895569-81-0) is a good general introduction to drums and drum making.
Resources
Heads - Mid-East Manufacturing
Bagpipe Valves - Scott's Highland Services
Where to learn to play tupan
The Eastern European Folklife Center runs two 1 week long summer camps, one on the east coast and one on the west coast, that always have tupan classes. Take a look at their website for more details. These camps are highly recommended because they are a total immersion experience where you will hear tupans played by numerous people in a wide variety of contexts.