Here is a list of all the useful URLs on Salesforce.com.

As URLs change frequently, if any of the following URL is not working, please leave a comment with details and I will update the URL. Also if you come across any other URL that is useful for Salesforce.com, do let me know. I will include that URL in the list here.

Salesforce.com
http://www.salesforce.com

Salesforce.com Pricing & Editions
http://www.salesforce.com/ap/crm/editions-pricing.jsp

Salesforce.com – Salesforce Videos
http://www.salesforce.com/video/

Salesforce.com You Tube Channel
http://www.youtube.com/salesforce

AppExchnage
http://appexchange.salesforce.com/

Salesforce.com & Force.com Developer Resources
http://developer.force.com/

Force.com Technical Library
http://wiki.developerforce.com/index.php/Wiki

Force.com Platform Fundamentals
http://www.salesforce.com/us/developer/docs/fundamentals/index.htm

Force.com Workbook
http://www.salesforce.com/us/developer/docs/workbook/index.htm

Force.com Cookbook
http://developer.force.com/cookbook/

Force.com Discussion Boards
http://boards.developerforce.com/sforce/?category.id=developers

Introduction to Apex
http://wiki.developerforce.com/index.php/An_Introduction_to_Apex

Apex Home Page
http://wiki.developerforce.com/index.php/Apex

Force.com Apex Code Developers Guide
HTML – http://www.salesforce.com/us/developer/docs/apexcode/index.htm
PDF – http://www.salesforce.com/us/developer/docs/apexcode/salesforce_apex_language_reference.pdf

Apex Code Best Practices
http://wiki.developerforce.com/index.php/Apex_Code_Best_Practices

VisualForce Home Page
http://wiki.developerforce.com/index.php/Visualforce

VisualForce Developer’s Guide
HTML – http://www.salesforce.com/us/developer/docs/pages/index.htm
PDF – http://www.salesforce.com/us/developer/docs/pages/salesforce_pages_developers_guide.pdf

Web Services Home Page
http://wiki.developerforce.com/index.php/Web_Services_API

Web Services API Developer’s Guide
HTML – http://www.salesforce.com/us/developer/docs/api/index.htm
PDF – http://www.salesforce.com/us/developer/docs/api/apex_api.pdf

Metadata API Developer’s Guide
HTML – http://www.salesforce.com/us/developer/docs/api_meta/index.htm
PDF – http://www.salesforce.com/us/developer/docs/api_meta/api_meta.pdf