Hackage is Haskell's repository of packages, used with Cabal (see below). Hackage serves the same functional role as CPAN for Perl, or CheeseShop? for Python.
Hoogle is a Haskell-specific search system which allows retrieval of Haskell-related tutorials, APIs, et. al.
Cabal is Haskell's de-facto package management system, a la 'eggs' for Python, 'jar' for Java, CPAN for Perl, and so forth. The author finds it bears more resemblence to Debian's APT than the others, and as such, relies on Hackage to serve as its official package repository.