We were sooo excited!!! He was in the bathtub and he looked over to the potty and pointed and said "pee." This isn't anything new, he's been saying that a lot, since he comes into the bathroom with us reguarly. So I asked him if he wanted to pee on the potty and he said yes. I got him out of the tub and sat him on the potty (we have a baby bjorn seat that fits on our toilet.. our bathroom is kind of small for a little potty chair) and at first, nothing happened. He's sat on the seat several times since we got it, but nobody really expected anything to happen. I've also been making small straining sounds to get him to try out those muscles... and tonight, when he did it, he actually peed! He looked kinda surprised, looked down to see what was happening, then got this huge smile on his face! We were all so happy and proud of him! I told him anytime he wanted to pee on the potty he could come get us and we'd help him.
Since he's only 22 months old, I really didn't expect him to do this, and I'm not sure when it will happen again... we are really positive about it though, whether he goes or not, we always make a big deal of sitting on it. And he could sit in a wet/poopy diaper for a long time and not care! So we'll see where it goes from here. What a big milestone!