Don't just read the following, instead, actively use the material, ie. type in code yourself (do not cut and paste!).. Reason: just like you won't learn to cook by just reading cookbooks or play golf just by watching it on TV, you won't learn to program just by reading (about) code. Put in practice or at the least, try out (type in) what you read - 'finger memory' is essential in programming.

MEL

Since MEL is a Maya-only language, comparatively fewer resources exist..

Books

Online resources

Maya and installation dirs


Python

There is a wealth of material on Python. Here's a small sampling.. You can discover much more by searching.

Books

Online resources

pymel links