Salesforce.com Web Services
Salesforce.com has exposed it's API as web services. In case you don't know, Salesforce.com is an online CRM system. Users are charged $65 USD per month.
They have samples in VB.Net and C# for VS 2002 and 2003. You can join free as a developer to get an account to play with. Check it out. http://www.sforce.com/us/
Have fun,
Paul