Hotkey to switch between Hangul and Latin input input modes with Windows 7 Korean IME?

AltGr+Shift (or right Alt+Shift) changes between Latin and Characters.

(Left) Alt+Shift changes the different language keyboards.

Right Alt will work - only if you are in editing mode (i.e. typing something in some textbox and not browsing windows etc)

Left Alt + Shift will switch between languages. You can modify this setting easily in the Languages/Keyboards setting.

I had this problem and found out that at least for me the button is Alt Gr.

This is because in Korean keyboard layout there is a button Ha/En there as seen in this picture:

Hangul layout

Alt+Shift changes between language layouts. This is different.