If you just need a letter sized printout of a property please use the Map/Aerial feature on the Parcel Search results since there are more features available.
The link above takes you to the Mercer County GIS 2011 site. To find a particular property just use the navigation controls or search tools on the GIS 2011 site. You can also search for parcels using the Parcel Search page and click on Map/Aerial on the results page.
For those that need to use the raw images download the appropriate jpg files from either 2001 or 2005.