Someone

jcf@compsoc ~/Cabal-1.8.0.4 $ ./Setup configure --user --prefix=$HOME/.cabal
Configuring Cabal-1.8.0.4...
jcf@compsoc ~/Cabal-1.8.0.4 $ ./Setup build
Preprocessing library Cabal-1.8.0.4...
Building Cabal-1.8.0.4...
Registering Cabal-1.8.0.4...
Setup: Unable to rename "/usr/lib/ghc-6.8.2/package.conf" to
"/usr/lib/ghc-6.8.2/package.conf.old"
ghc-pkg.bin: /usr/lib/ghc-6.8.2/package.conf: renameFile: permission denied
(Permission denied)