B.R.
Some children (you, your friend, and this often happens with little girls) potty train early. I did also. But pushing your child to do it when he is not ready is NOT healthy for him. It will make you frustrated, it will make him frustrated, and you'll all be miserable. The guideline I'm sure you know is 2.5, but many kids are ready earlier- just keep in mind it is much harder for boys to potty train (boys mature slower) so it is unfair for you to hold him to this standard. Make sure he sees both you and your husband go to the bathroom (a lot of people think this is weird, I know, but what better way to teach than by modeling? And if you act like it's some big deal private thing then he'll definately not want to do it) and talk about it- Izzy's 18 months and knows all about going potty- she's even peed in the potty three times. But I'm not pushing her at all, just encouraging and educating. I also got a board book (kind of by accident at the dollar aisle in target) called "bye bye, diapers" and she loves to read it- she clapps and goes "yeah!" when the little girl in the book goes pee pee. But I know she's not completely ready yet for a few reasons- 1) she can't pull her own pants down yet (I don't want her to have to rely on me to do this, I want her to do it on her own), and 2) she only tells me she has to go pee pee when she really just wants to take her diaper off and run around naked, ie, she really doesn't recognize the urge to pee and can't hold it (but she knows if she takes her diaper off she has to sit on the potty, then diaper goes back on).
What's the rush, though? I know, diapers are a pain, but potty training too early won't be much better, because unless he is ready for it physically, mentally, and emotionally, you're going to end up spending the next 6 months to a year struggling with accidents and battles of will.