The Internet Archive has a collection of over 1000 Parish Registers available to search for free here: http://archive.org/search.php?query=parish%20registers
Not perhaps the easiest site to search (although if you add the name of the parish or county in the ‘Search’ box it may cut things down a bit): and please note that some volumes (such as the first volume for Derbyshire) contain several different parishes, not all of which are tagged. In addition, some volumes shown as ‘Register of Births’ are in fact marriages.
But, with patience, you may be lucky.
I’ve added this to the ‘Useful Websites’ page.
