The Mileage Converter mentioned by McMilescollector is certainly the best place to start. It is not 100% accurate, but it generally shows if a program allows transfers (many do not), the path to another program (many times you must transfer to an intermediate program or two), and the approximate loss of value in process (you nearly always end up with less).

There is no harm in joining the free version of Points.com. They do need your security details to access your point balances. You will find that most programs which do allow transfers or purchases of miles or points use Points.com to implement these features.