I think one of these should fit the bill:
- An integration of NOLA (ERP), osCommerce (e-commerce) and CRM. OSSUITE is the only solution for small-medium enterprises (SME) in the global marketplace covering all areas from e-commerce, customer management, supply chain and accounting.
- The goal of this project is build a multi platform, multi lingual, web based timesheet and payroll systems using PHP and MySQL. This program will allow for complete automation of the payroll systems of a company. Users will be able to clock in and clock out from a simple web browser. User Clock in and Clock out can be controlled by specifying specific IP addresses from which the latter can clock in and out for work. Users will be able to view and print reports about their hours worked and work done during any period of time. Administrators will have web based control panels to completely customize the payroll systems. There will be tools like controlling access by IP address, generating payroll reports, edit employee timesheets, manage projects, getting payroll statistics and many other features.
Both are open source.