In my application I have a UITextField inside a UITableViewCell. If I click inside the text field and add some text I find that if try to move the          
        
I spent a lot of time on this but I finally think that I have it nailed.
The trick is that the table needs to be editable (i.e., its editing property needs to be set to YES). The good news is that you are now able to move the insertion point. Sometimes the magnifying glass doesn't appear or follow but your gesture always seems to work.
Does this still qualify as a bug? Perhaps. At the very least Apple's SDK documentation should be updated. I've raised a bug report with Apple to cover this (rdar://6462725).