My nephews go to a catholic school and they get a lot of religious education (too much for my BIL!!).

All catholic schools take a certain percentage of non-catholic students so your kids won't be the only ones not baptised.

Just out of curiosity, what school are you looking at? A friend of mine recently tried to get her baptised daughter into Newman for kindy and didn't even make the interview process, despite a glowing reference from their priest. They apparently had such a huge over application for the places available. I am still tossing up sending my girls to a catholic school but am now concerned about them even being considered for a place. We have a great primary school in our area but I've been told if your children aren't baptised you really need to send them from kindy if you want any chance of them going to a private high school, and we just aren't in a position to pay $10K odd per girl per year.