The main documentation website for NumPy and SciPy is at http://docs.scipy.org/doc/. On this web page, we can browse the NumPy reference at http://docs.scipy.org/doc/numpy/reference/ and the user guide, as well as several tutorials.
NumPy has a wiki with lots of documentation at http://docs.scipy.org/numpy/Front%20Page/.
The NumPy and SciPy forum can be found at http://ask.scipy.org/en.
The popular Stack Overflow software development forum has hundreds of questions tagged as numpy. To view them, go to http://stackoverflow.com/questions/tagged/numpy.
If you are really stuck with a problem or you want to be kept informed of NumPy's development, you can subscribe to the NumPy discussion mailing list. The e-mail address is <numpy-discussion@scipy.org>. The number of e-mails per day is not too high, and there is almost no spam to speak of. Most importantly, developers actively involved with NumPy also answer questions asked on the discussion group. The complete list can be found at http://www.scipy.org/Mailing_Lists.
For IRC users, there is an IRC channel on irc://irc.freenode.net. The channel is called #scipy, but you can also ask NumPy questions since SciPy users also have knowledge of NumPy, as SciPy is based on NumPy. There are at least 50 members on the SciPy channel at all times.
