How to move windows that open up offscreen?

I use this approach:

• Use Alt+Tab to switch to the off-screen application.
• Press Alt+SPACE to bring up the system menu (you won't see it because it is off screen)
• Press R to select the "Restore" menu choice to ensure the windows isn't maximized (you cannot move it if it is maximized)
• Press Alt+SPACE again, then M to select the "Move" menu choice.
• Press one of the arrow keys to initiate the movement.
• Now just use the mouse to place the window where you want.

If you are using a non-English version of Windows, the "R" and "M" menu choices will probably be different.

For Windows 7 and later users: +Shift+← or → will move the selected window to the monitor in that direction.

You can right-click the program's button on the taskbar, and then click "Move". You can now use the arrow-buttons on your keyboard to move the window where you can see it. Requires some fiddling, sometimes the windows get "stuck" on the monitors edges. You can also try using the mouse, but the keyboard is a bit more reliable if you can't see the window yet ;-)

Back before there was the task bar, I used to fix this problem with Alt+Space to bring up the window menu, then M for the Move function. The arrow keys would then allow you to move the window back on-screen.