This link to the wikidevelopers is another critical resource for Salesforce administration. Customization and implementation guides are here, as well as in the Help area within Salesforce itself.
Help Articles for using and administering Salesforce. This is your resource go-to guide. Use the navigation menu on the left to move through the modules and get training for Salesforce.
Salesforce Foundation starting points. This foundation is another great resource for Salesforce for nonprofits.
Shared calendaring Salesforce
Salesforce quick start
Dummies.com- Salesforce cheat sheet
Link to community threads in Salesforce Foundation. These forums are a great place to get free consultation and answers to questions.