String -> IO Handle -- generalized input

[Galen Menzel]

Hello.

I'm writing a little string-parsing function and I'd like it to be
able to get character-at-a-time input from a file or a string.  Is
there a function that takes a String and returns an IO Handle that
contains the contents of the String?  Something like C++'s
stringstream constructor?  Or is there a better way to do this?

Thanks very much.
galen