WinPython is a portable distribution of Python. In other words, even if it provides a working Python environment, WinPython does not install Python on your machine.
To install package on Winpython:
The WinPython Package Manager (WPPM) may be removed in the future, when "PIP" will get a standard Graphic User Interface, a Python program handling package managing tasks (install, uninstall or upgrade packages) for a portable Python distribution.
The main website for finding and downloading Python packages is obviously PyPI , the Python Package Index.
Please note that Christoph Gohlke's Unofficial Windows Binaries for Python Extension Packages provides tons of ready-to-install distutils packages. WPPM GUI frontend
WPPM has a GUI frontend which is known as the WinPython Control Panel.
to update PIP package itself and keep WinPython as a movable directory:
if you do a standard PIP upgrade (or launch "scripts\make_winpython_fix.bat"), all is good as long as you don't move the WinPython directory.
Old wiki page: http://sourceforge.net/p/winpython/wiki/WPPM/