Be sure to find literature on Python 2.5, 2.6 or so, not for 3.0 which is new and different enough (not backward compatible) to keep a n00b confused, and is not widely in use - yet.
Two excellent books:
The Quick Python Book, Daryl Harms and Kenneth McDonald, publ. by Manning. Somewhat out of date not having certain glamorous new features, e.g list comprehensions, but a great enjoyable book to get started.
Learning Python, Mark Lutz is a classic, publ. by O'Reilly.
Official standard tutorial, arguably the best place to start: http://docs.python.org/tutorial/
There may be useful tutorials here (i haven't been there lately): http://www.awaretek.com/tutorials.html
You can find tutorials and easy-going examples on any particular part of the Python language, for example on strings see http://www.hjcb.nl/python/Strings.html
, for numbercrunching use numpy (or scipy) explained at http://www.rexx.com/~dkuhlman/scipy_course_01.html
, and plotting data use matplotlib http://matplotlib.sourceforge.net/index.html
Also, "Dive Into Python" at http://www.diveintopython.org/
, if you are already a programmer knowing a few languages but new to just Python; this is a classic for that audience.
After mastering beginner level stuff, go explore Software Carpentry at http://www.swc.scipy.org/lec/intro.html