Creating New Interfaces
Assuming you've read creating new classes, creating a new interface is astoundingly easy. Right-click on your project or one of its packages in the Package Explorer and this time choose New > Interface. A shorter version of the new class window will pop up.
You'll note it's mostly the same. Enter a package name in the "Package" field if appropriate. Give the new interface a kosher name, a scope, and then specify any interfaces that your new interface extends by clicking Add. You know the drill by now. When you're all set, click Finish and voila! New interface.