Daniel,
There is no out of the box way to do this. A manual way could be:
- PM creates the project, Changes the status (custom lookup) to Ready for Resource Allocation
- RM opens the project, assigned resources as "proposed" booking type and saves the project, changes the Status to something like Resource Assignment done, ready for next step
- PM opens the project, and confirms all resources assignments meet his need, changes the booking type to committed and publishes the project
This is just one variation of the process you could use.
If you are implementing a workflow, you could enable some of thsi process through stages, and have notifications sent out.
Hope this gives you something to start with.
Prasanna Adavi, PMP, MCTS http://thinkepm.blogspot.com