The project is hosted on http://sourceforge.net/projects/phonemodeler/.
Your are going to need these reference materials if you want to help develop the Phone Modeler. You will need to have a Cisco Developer Login (or sign up for one) as well as Cisco IP Phones. Cisco does have a Phone Services Emulator that is Windows based, that you can use in the developer area of their website.
You will need a Cisco Call Manager environment preferably version 3.3.x. However this will also work in the Cisco IP Phone in SIP mode with third party Call Control Systems such as Vocal.
Phone Services Developer Guide
Developer Kit for Cisco IP Phone Services
Joining the Project
There are a number of steps you need to perform to join the sourceforge, then the project, then checkout and build the project.
1) Firstly join Sourceforge - http://sourceforge.net/account/register.php
2) Then join the project as a developer by sending me a message from your home page.
Installing the SSH Client and setting up WinCVS
Windows 32bit Access
The SSH client we recommend to most 32-bit MS Windows users is PuTTY. PuTTY consists of several separate applications arranged in a suite. PuTTY has fairly low system requirements and provides a graphical interface which most MS Windows users will find comfortable. The applications within the PuTTY suite you will most need in order to use SourceForge.net are the PuTTY program (a SSH client) and the PSCP program (a SCP client). PuTTY is Open Source software. PuTTY supports both the SSH1 and SSH2 protocols. Complete documentation is available for PuTTY.
PuTTY may be downloaded from http://www.chiark.greenend.org.uk/~sgtatham/putty/.
Other Operating Systems Support.
Most other operating systems Unix, Linux, BSD and MacOSX have already got a SSH client. Read Introduction to SSH for SourceForge.
Installing WinCVS for Sourceforge.
The recommended CVS Client for Sourceforge is WinCVS. The installation and configuration instructions are here.
3) Next you need to review the documentation on how to use the CVS repository from the project here. This explains what CVS client and SSH package you need to use to check in code into the repository.
Building the Project
4) Next you need to read how to build the project. This documentation is on this website and on the document section of the project.