iOS: How to make a UIButton get a blue shade when pressed?
[yourButton setBackgroundImage:@"normalimage.png" forState:UIControlStateNormal];
[yourButton setBackgroundImage:@"normalimage.png" forState:UIControlStateHighlited];
state = NO

if (state == NO) {
    [yourButton setBackgroundImage:@"blueimage.png" forState:UIControlStateNormal];
    [yourButton setBackgroundImage:@"blueimage.png" forState:UIControlStateHighlited];
    state = YES;
}
else {
    [yourButton setBackgroundImage:@"normalimage.png" forState:UIControlStateNormal];
    [yourButton setBackgroundImage:@"normalimage.png" forState:UIControlStateHighlited];
    state = NO;
}