He he he... I am potty training my 2 1/2 year old boy and he took his first pee in the bushes yesterday (I'm sure it will not be his last!!) Of course, he loved it!! I had to laugh the whole time, too cute!! For boys, the whole world in a urinal!!
I do not think you can totally prepare your toddler.. just be sure to give him extra attention after the baby comes!!
Opps, little type-o... For boys, the whole world IS a urinal not IN a urinal..

When new baby and I were still in the hospital, my hubby took my daughter (she was 3) to the gift shop and got her a "Big Sister" t-shirt and she picked out a present for her baby brother!! But, after the excitement was all over... it was an adjustment period for her!!!