This section lists some general Python-related resources. Blender scripting resources are listed in the next section.
www.python.org: It's the main site and very well organized, nevertheless some main sections deserve to be mentioned separately here.
www.python.org/download/: Download your full Python distribution here if you do not already have it installed or if the installed version doesn't match Blender's built-in version exactly.
For newcomers and seasoned programmers alike, the following pages offer some useful tutorials on Python in general and some 'how-tos' on specific subjects. All the articles on these pages have a fairly low learning curve:
docs.python.org/tutorial: It is especially worth reading for people experienced in other programming languages who want to learn Python. It covers most Python-related issues and should be sufficient for most people to get started with Python.
docs.python.org/howto: Detailed information on subjects such as regular expressions, Internet programming, and Python style.
More extensive information on the Python programming language and its bundled modules is available as well. These pages are a credit to their authors and maintainers because although exhaustive in their coverage and depth, they are still very readable.
docs.python.org/reference/: It is the main reference on all language structures such as statements, data types, and exceptions.
docs.python.org/library/: The ultimate reference for all bundled modules, built-in functions, and objects. Before you even think of programming something yourself, you should check this page to see if a module is already provided that covers your needs.
pypi.python.org/pypi: If the bundled modules do not provide what you need, chances are some third-party encountered the same problem and wrote a package to deal with the issue. If so, you'll probably find it on Python's Package Index.
code.activestate.com/recipes/langs/python/: Sometimes, you just need a code snippet, code example, or an algorithm to get you started. You might find it here.