go version 1.1.2

For example you need to install the webscoket pakeage

try 
         go get code.google.com/p/go.net/websocket
  catch

$GOPATH no set? 
              that you need set the GOPATH in the system environment variables and this path should in golang directory

no Mercurial?

download it

now try go get ... again.

find the file in your GOPATH and make it like golang original file structure  src->pkg->*  (pkg is added by myself)