BIG difference... but for a simple reason. Interfaces written for type libraries are as general as can be, and are directed at clients such as Visual Basic, and VB is designed to hold the programmer's hand as much as possible. To keep interfaces simple to VB users, the concept of a "property" is used. One may "set" or "get" a property value, so these two functions seem to be the same to a VB programmer (the object reference just moves to the other side of the equate operator). A "method" makes some change or performs some action involving the object.
To create the type lib, use MIDL on a command line like so: