What is the best modules for project resource management and timesheets?

I need to setup a basic environment for managing projects. I am open to use either Drupal 5 or 6. In that there is also a requirement to have a timesheet facility. I checked the timesheet module but that is only limited to D 4.7. I need a option to manage project resources, details, duration etc. I want to know a group of modules that could be configured to provide the similar functionality.

Thanks in advance.

Anirudha