title: Custom Task button "Log a Phone Call" in salesforce.com
body: <p>I'd like to create a custom task button that would create a new activity or task and default subject and a custom field "Activity.Type__c" to "Phone Call" when clicked.</p>
  
  <p>I got as far as defining the button, but need some pointers on what the content source and the actual code should be.</p>
  
  <p>Sample code and/or links to tutorials are greatly appreciated!</p>