Quickbooks payroll service is a pretty no-brainer approach. Inexpensive, integrates to Quickbooks, very simple to use, but not the cheapest solution out there. Bank of America also offers a payroll service that I've heard from a couple of people they got for free in exchange for using their other banking services, so you might look into that.

Years ago, Paychex used to offer great deals, but haven't talked to them in a long time, and they may have been swallowed up by somebody else.