There's a shareware Photoshop plugin that does just what you are asking
AGD Color Temperature & Exposure correction Plug-In
I have used it on a couple of occasions and it seems to work fine. I
can't tell from the website what the limitations are in the free
download version (I haven't found any so far), but there is a built-in
15 second delay (nag screen) when you select it from the 'Filter' menu
within photoshop. Works with V6, 7, CS.