It depends on the timeframe they lived - you can start with searching the census records for the head of the house and see what you find. You will have to have a general idea of where they lived for that, especially if you have a common surname.

You can also see if you have any luck searching the baptismal records on this site - most of the clergy were good at giving the parent's names.

I hope that helps, if only a little.

Wendy