Resourcing... a fun topic. First I do want to say that you should look at the new scheduling in EA or your preview sandbox and test it out. We have had a lot of good feedback from our RMs about it.
Now, every resource manager we have likes to do things a little differently so I'll give you some examples:
Let Laura said, we have two RMs that use "fake people" so that they can see the unassigned tasks in the Resource Grid or User Utilization tool. So if my Health Project Manager needs a developer, they assign Health Developer Person to the task. (All our fake people have Person as a last name)
For some it is just a basic list where they select a time frame (we have Today, Next Week, Next 2 Weeks, Next Month). It is an assignment report that is grouped by Project and then Assigned To and where the filter is Assignment Role ID equals whatever they are incharge of. That way the Resource Manager can see all work that needs to get done for the projects in that time frame and what has been assigned and what has not yet.
Some like to departments like Studio or Editorial just use the team functionality as there work is not really planned in advanced (we are working on it) and no matter how much comes through it needs to get done so they like getting the team requests and picking up the work. The RM then is just monitoring all the work that people have and can reassign things she sees fit.
We also have two agencies now that just have their PMs pick the people they want for a project and the RM montiors the workload and projects and is in communication with the Creative Directors to see if those are the best people.
Like I said, tons of different ways to do it. I tend to base it on the RM so we do have several different options but I wanted to make their lives easier not force them into doing something the way I'd like it.
But like I said, we have had some great feedback with the new scheduling tool so I would recommend playing around with that. (Although the fake people approach does not work that. You have to go back to the job role option.)