Speaking as a son and not as a father, if you intend to help your kids or do something for your kids. Do it, and dont complain about it.
Make sure they understand that you're helping them, and they should be greatful, but dont spend your spare time complaining about what needs to be done and whats being done.
I heard alot growing up about how expensive it was to have me and my brother and sister around, and being old enough to contemplate it now i understand it was my parents DECISION to have kids.
Set the rules before hand, not afterwards, no one is a mind reader.
Dont spend all your time reminding them that they're not grown-ups and letting them know that they dont know how tough the real world is, they live in the real world, just like you, and they'll find out as they go.
I suggest if its at all feasable you let your kids know what you do, and involve them in it, so they have an understanding of what daddy does.
That being said, from your personality i've experience on here, i think you're going to be a GREAT dad! Congrats.