If you do not have a copy of VMware vSphere 4.1 HA and DRS Technical Deepdive by @DuncanYB and @FrankDenneman then go here, buy it, and read it cover to cover. The book covers everything VMware High Availability (HA) and the Distributed Resource Scheduler (DRS) (and then some!).
Alan Renouf, co-author of another must have book – VMware vSphere PowerCLI Reference: Automating vSphere Administration, has put together a nice HA and DRS Audit PowerCLI script that can be used to gather information and check for best practices on your HA/DRS cluster based on the information from the Technical Deepdive book.
The script is run against your vCenter and creates a nicely formatted HTML report with all the HA/DRS related details of each cluster managed by vCenter. This gives you a detailed overview of your environment and the configuration of HA and DRS.
As of right now the script is based on the information contained in just the first 50 pages of the HA and DRS Deepdive. Alan Renouf is promising updates to the script as he works his way through the book.