There are plenty of them available online (both free and for sale), just
google "Excel Payroll Template"
If you're a payroll person and need to generate a manual check (or if you're
just looking to do a "what-if" on your own check), you can do it for free
online at
http://www.paycheckcity.com/netpaycalc/netpaycalculator.asp
As an aside: 20 years ago, I had a job processing payroll through an
automated service. It took me about an hour to build my own template in Excel
to quickly get the figures to generate the occasional manual check, creating
my formulas using the percentages and withholding considerations provided in
IRS Publication 15 and the equivalent state guide.
This was my first major Excel achievement. Not only did successfully
building it from the ground up inspire a lot of confidence in using Excel,
but it gave me a far better understanding of how income taxes work that I
wouldn't have otherwise.