Intuit’s Online Payroll allows small businesses to manage their employee information, payroll, and tax forms. Online Payroll integrates with QuickBooks Desktop and QuickBooks Online, to provide full coverage for small businesses. The mobile applications are very accessible and the iOS application was featured in an AppleVis podcast by Scott Howell.
Online Payroll is a subscription-based service. Costs are based on the number of employees and completeness of tax document creation. Prices start at $25/month + $2/per employee (February 2015). There is a free trial period and you can use a sample account on the mobile applications to understand how it works.