Learn MRI

The Basics of MRI
probably the best MRI learning material on the web.

e-MRI
lots of animations. A good supplement to The Basics of MRI.

Introductory NMR & MRI
a great video lecture given by Prof Paul Callaghan.

81Bones.net's MRI Resources
a very nice collection of online and downloadable materials covering from MRI basics to advanced sequences.

MRI: from Picture to Proton (on Google book)
a good introductory book.

MRI: the basic (on Google book)
an easy book with lots of figures.

MRI from A to Z (on Google book)
a quick reference if you want to know the terms and acronyms in MRI.

Learn fMRI

EPI and fMRI
an introduction to Echo-Planar Imaging (EPI).

fMRI 4 Newbies
very good online introduction covering all aspects of fMRI.

Advanced Brain Imaging User Training Course by Dr. Chris Rorden
very good course on practical aspects in fMRI theory and analysis

Dr. Mark Cohen's course on Functional Neuroimaging
another comprehensive course on fMRI with more technical details.

Learn Neuroscience

Brain Facts
An excellent overview of the brain provided by the Society of Neuroscience. PDF version available.

The Brain from Top to Bottom
good introduction to neuroscience provided by McGill Univ.