"zipping" two streams in the IO monad

How could I "zip" two possibily infinite streams obtained by IO operations, for example to return the infinite list of pairs of values read both from channel a and from channel b with getChanContents? In general, how does one implement a function like "getChanContents" wich returns an infinite list? Tell me just some pointer to information of course, I don't want an entire functional programming lesson :) Vincenzo