In addition to the sources provided earlier, I found some sources that might work for your needs. Because your request was largely about locating charts, I opted for a google image search, because you can limit the search by color (in this case black and white). As pointed out by the earlier comment, though, this is going to limit the number of results, so if you have photoshop access (or something like it) it might be good to open up the search. Assuming you don't have photoshop access (which would be understandable, because it's not cheap!) I restricted the search to black and white images, but this was frustratingly hard to maintain, and images with *some* color kept popping up. I'm including them, just because they're the most useful sources, I hope that's okay. I wanted to make sure my results returned were from reputable sources, so I searched for images related to the Congressional Budget Office, generally considered a bi-partisan entity (http://www.factcheck.org/2012/03/bogus-bipartisan-claims/).
So, what did I find for you?
Here's a Washington Post article analyzing CBO data, with some *mostly* black and white charts:
http://www.washingtonpost.com/blogs/ezra-klein/post/the-cbo-takes-on-income-inequality/2011/10/26/gIQAzcPqIM_blog.html
That link is long and could break, here's a shorter version: http://wapo.st/tMyVUZ
This is a Labor and Employment Relations Association report that has a lot of great charts about income inequality, including tax code benefits for the rich:
http://lera.press.illinois.edu/proceedings2011/appelbaum.html

Also, you should know that according to some of the articles I found in this search, tax rates on the upper income brackets has actually gone up in the last few years:
http://www.factcheck.org/2008/05/top-1-what-they-make-and-pay/
http://www.econbrowser.com/archives/2011/11/taxing_the_1.html
http://online.wsj.com/article/SB117668220910270761-search.html
(FYI, this last one is written by Ari Fleisher, former Bush press secretary, the opposite of a bi-partisan source)
I point this out not because I think that income inequality is disappearing or that tax codes in the US are unfair (irrespective of what I think, CBO and other sources have a ton of data to support those arguments), but because having been to a number of Occupy events, I know how important it can be to be acquainted with the other side's arguments. So I recommend looking over the links above for some additional information, if only to be armed with likely opinions from the other side(s).
Best of luck, let us know if you need additional information!