I can point you to some GREAT resources! First, a word about workflows in general.
Workflows are business processes that can be attached to any SharePoint list items.
A great place to start for great information and free resources is our SharePoint Solutions Workflow Resource Center. White papers, case studies, demos, blog posts — it's all here in one convenient place.
http://sharepointsolutions.com/resourcecenters/Pages/SharePoint-Workflow.aspx
A Good High level overview of Workflow & SharePoint can be found on Microsoft's site:
http://www.microsoft.com/downloads/details.aspx?FamilyId=DBBD82C7-9BDE-4974-8443-67B8F30126A8&displaylang=en
Visual Studio 2005 example:
http://weblog.vb-tech.com/nick/archive/2006/09/04/1753.aspx
A good Designer video:
http://channel9.msdn.com/ShowPost.aspx?PostID=197661
SharePoint removes links to workflow histories after 60 days. This can be increased. Here is a good discussion thread with scripts for increasing the 60-day limit.
http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=2272887&SiteID=1&mode=1
There's plenty there to get you started. Hope it helps.
