Is there a free (preferably public-domain or BSD-like license, but GPL will do) implementation of a multi-layer perceptron anywhere on the net?
I have textbook examples but the licenses are too restrictive, and although I can just about follow the math in the Wikipedia articles I'm not confident enough of getting it right and it's hard to test.
I've done a quick google search and found some free (as in beer) binary-only versions. I'm hoping to find an MLP which is part of a larger open-source project.
FANN (Fast Artifical Neural Network Library) is a great general-purpose neural-network library written in C but has bindings for just about any language you might want (C++, .NET, Python, Mathematica among others). Even better, it's open-source and licensed under the LGPL, so I'd imagine that would be fine for you.
Neuron.NET is another good alternative if you're using .NET (also open-source), though it's licensed under the GPL.
Hope that helps.