I see many libraries and examples for writing websockets servers in Haskell, but what about clients? Are there libraries for this?
Websockets package supports client applications
http://hackage.haskell.org/packages/archive/websockets/0.7.0.0/doc/html/Network-WebSockets.html#g:12
See an example:
https://github.com/jaspervdj/websockets/blob/master/example/client.hs
The websockets package contains the websocket client as well. After starting a connection with connect you write the client code in the same way as for the server using the websockets monad.
websockets
connect
I would make a client using client websites. For a good library see: https://code.google.com/p/jquery-websocket/