Will makes a good point about bundling it with other services. A Profesisonal employer Organizatino can assume the responsibility of your payroll administration, work comp insurance, and employee benefit administration TO INCLDUE 401(k).
In a large group PEO 401(k) program in most cases you dont have to worry about annual admin fees or even being forced to match if your not ready to do it.
I know a few PEO that have great programs that could help you. Contact me should you have any questinos.