If you think he's ready, this is a skill that you can help him learn and it can be a really wonderful bonding experience for you, especially with a new baby at home (positive attention). Have a week of build up before the training starts. Start by reserving a half dozen potty books at the library, also reserve some of his favorites, Thomas, whatever he likes. Go check them out and get about thirty more regular books and start reading the potty books every day. You are going to reward him for SITTING on the potty, something he can do, not going, something he doesn't control yet. Ask a friend to go through her kids toy box and give you 15 to 30 little toys her kids aren't playing with anymore. Match box cars, dinosaurs, whatever and wrap them up. You're going to let him hold a prize while he sits on the potty and you read a book. He gets to open the prize when the book is finished. The idea is to get him sitting there long enough to pee on the potty. The week before, you or hubby make extra meals and put them in the freezer so you can really concentrate on this. Also, let your son pick out the big boy underwear at the store. Get him a potty that makes noise when you go if you have the money and are training on a potty (vs. toilet). It's instant notice to him that he went. When you get home, see if he'll try it out. If not, you go on it so he knows what will happen. Show him how you dump the pee in the potty and flush. Have a day where you take him to SIT on the toilet at many different places like a store, the library, the park, etc. This way he won't be scared of them when he's potty trained. Make a list of all the "big boy" things he's doing lately, or things you could start letting him do. Setting the table, answering the phone, walking next to the cart at the grocery store, whatever you've noticed or are comfortable with. Now you can talk about how grown up he is and that he'll be peeing and pooping on the potty soon. Think of this as the build up we have around Christmas, or your holiday of choice. Wrap up the underwear and have hubby give it to him the day you start. I agree about doing it on the weekend when you can really focus on it. My son had accidents for three days and then got it. That was with me playing with him constantly, reading him stories, and doing happy dances and being silly when he went on the potty. Remember, it's a skill to be able to go on command (i.e. when you're sitting on the potty, and not ten minutes later.) Do not ask a toddler if he wants to go, take him and make it fun, but get him into a routine. We always pee on the tree in our front yard before getting into the car for instance, because that's more fun than the potty. Also, it was helpful for me to write down when he went. I found I need to take him every two hours in the morning but much less in the afternoon. After the first week my son was still pooping in his pants. He wanted a dump truck. I bought it for him and told him when he pooped on the potty he could have it. A few nights later he asked about it and I told him the same thing. The next morning he got up and kept trying to poop on the potty until it happened, and he was so proud.
A few things to know going in: plan to do a lot of laundry. Also, my son took an extra hour or so to fall asleep at night because he was so excited about his new skills. This happened the day he went on the potty, the day he told me he had to go and made it on time, the day he decided to poop on the potty and did, the night he got to sleep in his big boy underwear. You have to find some patience and just be proud that he's accomplished something. (Hard when you're sleep deprived, I know.) I want to end with this...it can be fun and fulfilling. My son told me each day he was "having fun with mommy" and I think it was due to the extra attention I gave him and how silly I was. And since he was naked except for his big boy underpants, I loved reading and getting hugs and "skin" contact with him that I hadn't had since he was a baby. Good luck!