We first took the training wheels off Ian's bike on April 24, 2013. This was the result:
Although he was perfectly capable of riding without the training wheels, I guess he didn't love it or it scared him too much because after that, he didn't want to ride his bike. I begged my husband to put the training wheels back on so that we could enjoy the rest of spring and summer. Reluctantly, he agreed to do so.
Now, roughly 6 months later, we tried again and we had great success:
Hooray Ian! Now if you could just stop panicking and screaming at me, we'll be golden. :-)