finding location of specific characters in UILabel on iPhone

The basic tools for measuring text on iPhone are in UIStringDrawing.h but none of them do what you need. You will basically have to iterate through substrings one character at a time measuring each. When a line wraps (the result is taller), split after the last character that did not wrap and add the line height to your y coordinate.

- (CGSize)sizeWithFont:(UIFont *)font forWidth:(CGFloat)width lineBreakMode:(UILineBreakMode)lineBreakMode;