This project was originally hosted on Google Code (http://code.google.com/p/lutheran-lectionary/) but is no longer maintained there.
The Lutheran Lectionary Project provides a PHP based library for abstracting out the Church's lectionary calendar, and enables the development of web applications utilizing lectionary-based materials. The library provides methods for calculating the week of the church year based upon a given date. The project primarily supports the calculation of Sundays within the Historic One Year Lectionary, but also supports calculating the Michelmas variation and hopes to expand to support other variations in the various Lutheran lectionary traditions.
This project serves as the algorithim by which http://sanctus.org is built upon.