I agree with what Karen A. says. Signs that he has bladder control can be seen by checking what length of time his diaper will stay dry (when he is awake). If it's always wet, then he may be interested but not have the control needed. If you have a hard time trying to tell if his diaper is dry or wet (especially with disposables), you can stick a piece of toilet paper in with his diaper and see if that got wet when you check his diaper.
I also think they need to know how to make the pee come out and that takes some practice. One of my kids would sit on the potty and get frustrated because the pee wasn't coming.
But you can introduce him to the potty at any time. I exposed my kids to their potty chairs on the early side and let them get over the play factor first. In the beginning it was just a "Hey, want to to try the potty." and if they wanted to great, otherwise I didn't push it. Or I'd take them with me into the bathroom so they could see what it's all about.
When it looked like they knew how to make the pee come out on demand and I saw that they could keep their diapers dry, then I became more active in potty training. I used a timer in the beginning and we would try every 20 minutes to start....especially when I put them in underwear. It was sort of a modified potty training boot camp....real casual in the beginning and then there came a point where I just dove in and said, "Let's go for it." We had 1 false start with each kid, where they each got frustrated and I backed off and tried another "no more diaper" weekend 2-3 weeks later. Mine weren't really trained until 3.5ish. It was a slow process but it was relatively stress free...just inconvenient at times.
I also suggest waiting until after you move to really dive into potty training. I think it's fine to expose him to it now and see how it goes, but changes like a new house can sometimes cause regressions. Plus I imagined it would be convenient for you not to have to worry about if he is going to wet his pants while you are getting ready for the move and actually moving.