All type of printable and accurate rulers on this site: one foot ruler, metric rulers, centimeter and inch rulers, yardsticks and more.

Visit http://www.vendian.org/mncharity/dir3/paper_rulers/

Online ruler that includes centimeter, inch, and pixel measuring formats.  Both horizontal and vertical formats provided.  Visit http://www.piliapp.com/ruler/

Online ruler in actual size based on monitor size and resolution.  Ruler for iPhone and printable rulers also provided.  Visit http://www.myonlineruler.com