Someone made a few more notes here:
http://forums.animesuki.com/showthre...676#post325676
But there are many more things besides that were changed in the anime. For example in the anime, I don't think they ever explain why Kumi went to watch Miyata's match, etc. It doesn't make much difference to the plot, but if you consider yourself a true Ippo fan, you should go over and read it from volume 1.