"Drag" selected text using the keyboard?
Your best bet would be to use MouseKeys. It's one of the accessibility features of Windows 2000, XP, Vista and 7.
Apart from using MouseKeys, it's not possible out of the box. You could probably create this functionality using something like AutoHotkey.
I just know moving lines in some editors. In Notepad++ it's Ctrl+Shift+Up/Down which moves the line up or down.