ATTENTION:
There is another project which has the same name:
http://packages.debian.org/sid/vim-addon-manager
The author (Jamessan) is fine with this project sharing the same name.

VIM ADDON MANAGER (VAM)
=======================
1) installation, configuration:
   http://github.com/MarcWeber/vim-addon-manager/blob/master/doc/vim-addon-manager-getting-started.txt)

The following text is a common github README file so that github visitors
immediately see what VAM is about:

VAM installs and updates additional scripts augmenting the feature list of the
text editor Vim.
It also handles plugin dependencies and puts each script distribution into its
own directory resulting in a painless installation management.

Supported PLUGIN SOURCES: git, mercurial, svn, bzr, www.vim.org, ...

Being 100% pure VimL (depending on some additional tools such as curl) it should
run everywhere. [1]

Feature list:

- declarative script management (example lines that should go to your .vimrc):

   set runtimepath+=/path/to/vam
   call vam#ActivateAddons(["snipmate","vimdevplugin", .... ])


- optional manual runtime activation of scripts:

  :ActivateAddons plugin-name


- update feature:

  :UpdateAddons [optional name list]

  This even tries to keep your local modification to archive based
  installations ! [2]


- a function which configures plugin sources:

  1) www.vim.org (the plugin list is updated daily by a cron job)

  2) some scripts have been added manually. Some of them are development
     versions which are also contained in 1)

  Contact me and I will add additional sources.


- community driven: several maintainers & contributors providing feedback and
  fixing bugs. Thanks to you all! (list provided in the documentation)


Continue reading the documentation: 
  doc/vim-addon-manager-getting-started.txt
  doc/vim-addon-manager-additional-documentation.txt

I could quote several people who told me how "awesome" this small tool is.
But I prefer letting you explore it yourself.

[1] most testing has been done on Unix environments
[2] diff tools (diff and patch) required