How to drag & drop to a "time line"

I have been asked to add a drag and drop interface to a planning tool. The user wants to select an icon from an explorer style tree in one window, and drag it onto the desired position on a time line (i.e. a horizontal graphical representation of a period of time). I have not done anything like this before. Is it possible in VB? If so, where can I find code examples, or learn how to do it? Many thanks.