A good place to start is the Haskell wiki:
http://haskell.org/haskellwiki/Haskell
On the left, look under "Learning Haskell" -- there's all kinds of
great stuff linked from there. I would also suggest hanging out in the
#haskell IRC channel on
irc.freenode.net -- it's a great place to learn
and ask questions.
If you give us more information about your programming/mathematics
background, why you're learning Haskell, what you hope to get out of
it, etc. I'm sure people could also give you some more specific
suggestions.
-Brent