Thanks for the link.
Unfortunately, the OSX only works for Leopard, and I initially used the Debian package for GHC (6.8.2) and Hugs but no cabal-install in there, and then used source to get GHC6.8.3. I still can't get cabal-install on.
I think the main point though is that Cabal and cabal-install are not straightforward to install (I must be pretty close to trying all versions by now), and the packages they require aren't always straight forward to install, which is why I think more, human readable, dependency information could be shown on Hackage.
I'm already sold on using Haskell so I'm persevering, but I think anyone who was just interested and had this trouble would have given up long ago, and likely you wouldn't have heard from them.
Iain
http://packages.debian.org/search?keywords=haskell