how to set button x and y for iphone

Question

ok this is my updated code

- (void)addImageSubViewAtX:(CGFloat)x atY:(CGFloat)y {
    CGRect myImageRect1 = CGRectMake(x, y, 32.0f, 32.0f); 
    myImage1 = [[UIImageView alloc] initWithFrame:myImageRect1]; 

    [myImage1 setImage:[UIImage imageNamed:@"glossy-3d-blue-orbs2-116-icon.png"]]; //food-icon.png
    myImage1.tag = 1000;

    myImage1.userInteractionEnabled = YES;


    //[myImage1 setShowsTouchWhenHighlighted:YES];

    [self.view addSubview:myImage1];
    [myImage1 release];
}

and i am usong this to display

[self addImageSubViewAtX:220.0 atY:170.0];
    [self addImageSubViewAtX:70.0 atY:90.0];
    [self addImageSubViewAtX:70.0 atY:250.0];

now tell me how you gonna detect colsiong for each image ????