Tiled Background Image: Can I do that easily with UIImageView?
If I understand your question correctly you can use colorWithPatternImage: on UIColor then set the background color on a UIView.
If you must use a UIImageView you can do the same but whatever image you place in the image view will draw in front of the tiled image.
To get alpha to work with pattern image, make sure you have the following set:
view.backgroundColor = [UIColor colorWithPatternImage:aImage];
view.layer.opaque = NO;