I'm hoping this is the correct place to post this if not please go easy on me as this is my first post. I have been stupid enough to buy common cathode rgb leds I'm using 74ch595 shift registers and trying to use madworms code with not much luck i'm getting the sort of patterns and lots of colour. the thing i need help with is changing the code to work with common cathode leds if this is possible PLEASE HELP.
Brilliant Thanks for your reply here is the link to the wiring diagram and to the code I'm trying to use http://francisshanahan.com/index.php/2009/how-to-build-a-8x8x3-led-matrix-with-pwm-using-an-arduino/
http://blog.spitzenpfeil.org/wordpress/wp-content/uploads/2008/10/matrix_code.pde
when its multiplexing 7 row are on and one row is off the same is happening with the colour mixing I need to invert all the output pins on the shift registers
Its the same as this http://picasaweb.google.com/lh/photo/4m0f5w6KA1bAIHIswXBFcg?feat=embedwebsite but with common cathodes instead of common anodes same circuit same code I've just got the wrong leds
so its not just a case of changing the code to work with common cathode leds I will need to get the correct leds Thanks for your help. I still don't understand why as the shift registers source and sink current
Ok Thanks for your help. 
but he is clearly using 74HC595's ...
I've sent madworm a message regarding this problem and he has replied with this link http://pastebin.com/3FSZpLND I haven't tried it yet but if anyone else has the same problem it should help them to Thanks again for all your help.