In case someone cares...

http://wsuonline.weber.edu/wrh/words.htm

As an editor, I often see people make these mistakes:

effect/affect
ellicit/illicit
they're/there/their

I misspelled "mispelled" here the other day for the sake of comedy and no one laughed.

Very helpful PF. that goes into my favorites immediately

Another good one, much more detailed: http://wsu.edu/~brians/errors/errors.html#errors

I probly didn't even notice .

Further(advancement) and farther (distance).

When writing, I have a sec to think about these two and keep them straight. When speaking, I've been known to mix them up.