iphone ios version and sdk version

hi i am trying to submit my app to the app store. i have my target set to ios 3.0 and sdk set to 4.2(latest). Should i build my app having my target ios set to 4.2 as well? What does apple want me to do ?

Target just means the lowest firmware setting you want your app to be run on. It does not really matter and I don't think apple cares one way or another. If they do, they will tell you after you submit your app.