Before going out and buying it I consulted my sister, the pediatrician. Yes, this is the same sister who has been kind of a bitch about his name and has only seen him two times in his 3+ months of life. So yeah, she's been a crappy aunt, but she is a great doctor and I trust her advice.
Anyway, we picked up some cereal and gave it a go.
He wasn't sure about it at first, but once we got going he was a big fan. He was actually yelling at me because I wasn't feeding it to him fast enough.
I tried again today and he wasn't overly interested, though. I guess it will take some time, but at least I know it didn't mess with his tummy and that we can start trying some other cereal in the near future.