pip is a replacement for easy_install (from pysetuptools).  It uses mostly the
same techniques for finding packages, so packages that were made
easy_installable should be pip-installable as well.

pip is meant to improve on easy_install.  Some of the improvements:

- All packages are downloaded before installation.  Partially-completed
  installation doesn't occur as a result.
- Care is taken to present useful output on the console.
- The reasons for actions are kept track of.  For instance, if a package is
  being installed, pip keeps track of why that package was required.
- Error messages should be useful.
- The code is relatively concise and cohesive, making it easier to use
  programmatically.
- Packages don't have to be installed as egg archives, they can be installed
  flat (while keeping the egg metadata).
- Native support for other version control systems (Git, Mercurial and Bazaar)

pip is complementary with virtualenv (can be found at SBo), and it is
encouraged that you use virtualenv to isolate your installation.

pip requires pysetuptools.