If you’re interested in capacity planning or resource planning here are a couple of nice sites that you might want to check out.
Capacity planning systems have evolved nicely over the last few years. The system that I like the most can do both scheduling and capacity planning. A good system will show you a schedule as it pertains to a best fit scenario and it will also give you the ability to show a capable to promise scenario. The schedule shows the plan as if it jobs were executed at the last possible date so that you can see where holes in the schedule exist.
A schedule that allows the user to visualize the timelines where capacity exists can be valuable. Perhaps the largest payback to this type of capacity view is found in sales. If you can see that a given resource has the capacity to insert a new job in a given timeframe. It becomes possible to promise customers expedited service on inserted orders without breaking promise dates. This can be a real boon for the sales and marketing department.
Another view that is handy is a view of overall loading. These views are generally most important at a master scheduling level. The ability to load work centers at an enterprise level can allow companies to run the most efficient work centers during non peak production cycles.
If you’re interested in more information on Capacity Planning or Production Scheduling you should check out the Capacity Planning Site. This site has some really well done articles on advanced planning systems.