Is there anyway of reading the contents of an external applicaiton's window?

Maybe it's just a problem with the application whose window I wish to read (because it is some kind of 'secure' telnet application), but even using the SPY++ program with MS Visual Dev Studio I have been unable to find any kind of messages that seem to be printing/displaying text in that window.

None of the WM_ or the EM_ messages have proved at all useful in this matter.
Any other suggestions?

regards,

John.