Altavista's technique may seem very complicated to break with OCR,
but the solution is not to try with OCR.
They aren't generating their "skewed letter" images on
the fly (that would be hard to do for the same reasons
it would be hard to parse) They have a finite set of images,
and by finite i mean on the order of about 200.
it would take about 15 minutes to write a script
that downloads all of them, and about 45 minutes to do
the data entry neccessary to map an image number with it's
secret code.
not that any of us would wnat to do that. :)