First of all, install moveAddict from Kapeli just like any other application. Follow the on-screen instructions and it will place a menu in the upper right System Menus area of the menu bar. You can set the application's preferences from this menu. The application will function in a limited mode until registered.
To move a file:
- Select the file you want to move (in a new Finder window or the desktop)
- Press Cmd+X
- Navigate to the folder where you want to move the file to
- Press Cmd+V
To merge folders, repeat the steps above, moveAddict will show an alert asking if you want to fully replace folders or merge to them.
[crarko adds: I tested this, and it works as described. Worth the $4.99 if you need the functionality.]

