Plugin for Tracking Time within projects…

I need a plugin that can track time spent on different tasks.
I need it to be per Company, Project and Task and User.

Only logged in users should be able to read and write.

Each Company may have many Projects and each Project may have many Tasks. Each Task may be done by several Users.

Since I don’t know what to call this plugin I can’t search for it!

Is there a plugin that does this?
What to search for?

// Anders