Character encodings and codecs

[Grumfish]

I'm trying to read and write files with differend character encodings.
I would like to convert a file from one encoding to another. I assume
I should use the codec module but I'm not sure how. How can I read in
a part at a time of a multibyte encoded file without destroying the
text?

Could some one please post a short example of converting a file from
one multibyte encoding to another without reading the whole file into
memory?

Any online tutorials would also be very helpful.