windows 7 - Hold a key to temporarily switch keyboard layout?

I am using two different keyboard layouts on my keyboard. I can switch between them easily by using Alt+Shift shortcut.

My question is whether it is possible in Windows 7 to hold some key to change keyboard layout temporarily?

Background: I am using English keyboard for programming, I would like to write comments with accents, and alt-shifting to write accented letters and alt-shifting back feels very clumsy.

This question asks the same question for ubuntu, but I have no idea how to do this in Windows.

Edit:
As by the Dave Rooks comment, using AutoHotKey works quite well. After some encoding related head banging, I decided to go with this straightforward if not so pretty script (I ended up listing all the letters in the alternate layout that I wish to use):

!_X_::Send {Alt Down}{Shift Down}{Shift Up}{Alt Up}{_X_}{Alt Down}{Shift Down}{Shift Up}{Alt Up}

where _X_ corresponds to a letter on the key in the current layout.