Jon is essentially correct, but it's not always true in that way. I think it depends on the speaker - some use it exactly the way he said, but some (like myself) use them interchangeably. These two phrases aren't really set in stone, because they're not truely proper English. However, they're not slang either... they are somewhere in between.

I agree with Bill. There's not much difference, although saying 'fearful of' sounds more like talking about a person or object, where 'fearful about' sounds like it would refer to an idea. Saying 'be afraid of' is much more commonly used.

Diary 2011-2-24

Today I learned so many surprising things. One of them is that our vice-chairman has worked in the company for about nine years which makes me worship her more. She works so hard and she always keeps working, even if the boss is not in. Then this afternoon my colleague went  with me to learn on the fifth floor and we stayed there the whole afternoon. Our business chargeman told us something about our products. From her,  I knew that we are selling four series products including 1101# (flame color calabash candle) 1102#(flame color spiral candle) 1103#(flame color straight candle) 1104#(flame color number candle), and that we have three main packing ways such as display box, display board, and simple packing. I think international trader is not a easy position, so I have many things to learn. Let us make a little progress every day.

First notebook entry: Introducing myself

I am a boy! Ok, l want tell you, I am a boy and my english is very poor!

Introductions

I've always been fascinated with language, but until about a year ago it was mainly with my native English. I speak survival Spanish and am currently teaching myself Italian by reading Il Messaggero, a native Italian newspaper. I'm intending to get to a fully conversational state with Italian, then I want to learn... well, I'm not entirely sure yet, but I'm thinking French and German, afterwards.

-Jeremiah

realized after I clicked submit that this was supposed to be in Italian. oops!  the next ones will :P