Ugh, having some trouble here...
I have 4 display labels in Interface Builder set up as IBOutlets in the view controller.
I\'ve set them up with these names
You have the right idea, but you should pass valueForKey: to self, not UILabel, assuming its self that owns these properties.
myLabel = [self valueForKey:[NSString stringWithFormat:@"label%d", randomInt]];
As a side note, this is probably better done with an IBOutletCollection. In Xcode 4, select all of the labels and drag them to the header file. This will generate an IBOutletCollection NSArray containing all the outlets. You can then pick a random index from that array. It is usually unfortunate that IBOutletCollection stores its outlets in a non-deterministic order, but for your case it should be fine.