Census Links is a growing catalog of links to transcriptions of census, tax lists, birth, death, marriage and military records, all freely available to help with your genealogy research.
The following site contains Census Index's for Bucks County, PA for the years of 1790, 1800, 1810, 1820, 1830 etc.
From the Bucks County, Pennsylvania GenWeb
Marriages from the docket of Isaac Hicks, Justice of the Peace, Bucks County, Pennsylvania. From Tiana's Genealogy in Pennsylvania Homepage
1890 Special Schedule (Almshouse) Bucks County, Pennsylvania