Is there a way to find out the type of a variable inside a function?

I'm learning Haskell, and I've been reading through various source code examples. I find the ":type" commend in GHCi very helpful in finding out what the type of top-level declarations are. However, it only works on top-level declarations (as far as I know). I find myself looking at code like f x = ... where g = ... wondering what f does, and so I try to figure out what the type of g is... and I get lost pretty quickly! :-) Is there a way to find out the type of g? Thanks! Andrew