It's very easy to Left-Align CCLabelTTF, but CCButton seems to have a problem with alignments.
button.horizontalpadding = CCTextAlignmentLeft;
I dont this there is a CCButton class in cocos2d. I assume you are talking about CCMenuItelLabel. Try this way:
CGPoint rightAlligned = ccp(1.0f, 0.5f); CGPoint leftAlligned = ccp(0.0f, 0.5f); button.label.anchorPoint = leftAligned; //For left text align button.label.anchorPoint = rightAligned; //For right text align