Mail-in-a-Box includes a check like this in its setup script, actually. [I'm the guy behind the project.]
However, I have to say, I had occasions where the IP was not listed on any RBL, but Yahoo was still flagging my IP.
I don't remember the exact error Yahoo were returning, but I think it was basically blocking all email... Perhaps even from the entire network range, since it was listed as residential or something of that sort (apologies, but I really don't remember the exact details, it was quite a while ago)