Where and how does the Bleach anime diverge from the manga?

The answer best showing where the anime and manga differ, while also answering where to start reading (manga chapter 480 BTW) is the answer by Logan M to this question : Which episodes of Bleach are filler?

I've read all of the manga and am currently watching the anime. It has been pretty dang accurate up until the episodes in the 60's where they kind of went off and created these whole other bad guys and this big plot that wasn't in the manga (the soul sucking vampire things... I can't remember their name). But apparently by episode 110 the anime starts back up and continues with the manga plot line and everything. But besides that I think that the manga and the anime are pretty similar :)

Bleach anime ended in March 2012, with the episode 366. It ends after (spoiler if you haven't finished the anime yet)

In manga, that arc ends with chapter 479, "Goodbye to our Xcution!!". The anime is not airing now, but the manga goes on, with the new arc starting with chapter 480 called "Final Arc - The Thousand Year Blood War".

I only watched the anime, but I know it stopped in March 2012, when they caught up with the manga. It was the 'Lost Agent arc'.

So I suppose you best bet is to start reading the manga that was written from around that time. Volume 49 of the manga is also called 'The Lost Agent', so that seems where they left off.

But again, I did not read the manga, so this is only a guess. I also cannot tell you how much the anime diverged from the manga.