First, the official Symantec-published documentation is at the site shown in reecardo's post. The most recent version of Workflow is 7.1 SP2. Start with the release notes and HOWTO66292 (best practices for configuring your Workflow setup, written by one of our Workflow Specialists).
Follow the instructions in the Installation and Configuration Guide to install and configure the product. Once you have Workflow installed, the User Guide is your next reference. We also publish a Component Guide, which explains what many of the most common Workflow components let you do.
Second, the Workflow SWAT site was produced and is maintained by Workflow specialists, some of whom are Symantec employees. It contains a great deal of very useful information, including videos. Note that this is not an official Symantec-sponsored site.
http://www.workflowswat.com/main.html
On Workflow SWAT, start with the Get Started tab.
Third, you can also take a virtual or instructor-led Symantec Workflow administration course through the Symantec training team:
http://www.symantec.com/training/product_training/detail.jsp?pkid=workflow_solution
Good luck, and reply if you do not find the information you need so that we can incorporate it.