This is on my iphone 4S 5.0.1

I wanted to change the color of sms bubbles without using winterboard and did some digging around with ifile.
The easiest way to do this is have ifunbox and photoshop, after connecting ifunbox navigate to
system/library/privateframeworks/chatkit.framework here you can see all the stock bubbles and colors, I would
copy this folder to your desk top or wherever you want to save it and keep it as an orginal backup

changing colors is as simple as opening each bubble .png in photoshop changing to a color of your choice and
after your done with everything respring your device and there ya go