This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
Start by selecting a SSO (single sign-on) product to use and then dig into the selected vendor's/product's documentation. Most companies I've seen implement SSO have bought Netegrity SiteMinder (which costs god-knows-how-much) but you'll probably want to look into other options as well. Here's some links I found by Googling: