You're in a tough spot, no doubt about it.
You probably don't need to hear this, but I'll say it for the sake of other readers. In my opinion, you shouldn't be having sex if you're not ready or willing to be a parent. No birth control is 100% reliable. Abortion isn't a back-up plan (especially if you haven't discussed it in advance with your partner).
As for your questions, I'm not a lawyer, and some of the specifics will depend on state law, but in general:
A father is responsible for financially supporting his children, whether he wanted them or not. (Unless they are adopted by someone else.) A father won't be forced to see his children, but it would be a lousy thing not to make yourself available.
Here is more from WikiAnswers contributors:
- In most cases the biological father is equally responsible for supporting a child/children. If in a situation where the couple are not married and the male does not voluntarily admit to being the father, a paternity test must be taken before child support and/or custody or visitation issues can be addressed. Some states allow a parent to petition the court for a voluntary relinquishment of parental rights and obligations. Contacting the clerk of the domestic or family court in the county or city of residence will help provide more specific information.