Thank you, those of you who commented or emailed me about giving a toddler a haircut. Following what you said, I decided that I could do it myself. And in fact, I enjoyed having control over how short it would (or wouldn't) be, instead of handing him over to a salon.
It took me a little while to get started. First I had to take some "before" pictures of his long hair. It was the perfect day for it - this was certainly not one of those rare times that he had lovely curls.
The straggly before pictures:
Then I spent several minutes posing the scissors near his head while I thought about what I was actually going to do with them.
Finally, I just started cutting. And it actually wasn't that hard.
Here's how it turned out (while his hair was still wet). I wish I had some better "after" pictures, but the only time his hair is freshly washed, dried, and brushed is right before bed. The rest of the time he always seems to have bed head, or sweaty hair with sunscreen in it!