Numerical Methods For Differential Equations



Hello, I'm new to Maxima and am currently enrolled in a Differential
Equations course at college.  In our class we use Matlab and
Mathematica to solve equations both symbolically and numerically. 
However, due to their prohibitive price and my interest in open source
software, I've installed Maxima on my personal computer (a Mac).  The
symbolic methods in Maxima are spectacular so far, but I've been
confused about the numerical methods.  In a few places on the internet
I've heard mention of an NDIFFQ package containing an rk4 method
amoung others, but such a package doesn't exist in the default
installation.  So my questions are:

Is there a way to solve differential equations numerically using Maxima?

Is there a way to plot slope fields using Maxima?

Thank you very much.

Ben