The Happstack tutorial [0] is pretty great and I just put together a bare-bones compiling Happstack server [1]. That might be a great way to start. Happstack is a fairly unopinionated web package, so there's a bit of elbow grease needed still, but it's my favorite.

[0] http://www.happstack.com/docs/crashcourse/index.html

[1] https://github.com/tel/happstack-heroku-test