I am planning to develop a freely available project management site.

This is a open source projects.

With following features.

1. User management
2. Listing bugs
3. File management with version management
4. Record of time when the developers worked.
5. Knowledge records.
6. Tasks assigned and its status.
7. Discussions.
8. Public messages.
9. Planning
And many more...

What I am seeking is what language I can use to develop this open source project.

I also want to know anybody want to participate with me.

I also want to how much time it takes to develop this project.

With Regards,
Mahavir .D