It was pretty much simple to see resource utilization and availability in Project server 2003. Simple open the project and go to resource usage view. Project server 2007 now has some changes to the system. As there are changes in terms of Projects, Resources and teams so Bill Raymond has blogged about the ways where we can see resource utilization;
First, you typically start with a resource stored in the Enterprise Resource Pool (which is stored in a SQL Server database). Once you assign a calendar to the resource, Project Server will understand what you’re typically week’s capacity looks like. With this knowledge, Project Managers can assign a resource to tasks in their project plans. Once published, the Project Server website (Project Web Access) will display views show how much a resource is utilized, when they are available and what the future outlook of that resource’s availability might look like.