Photoshop raw plug-in not working?

I have a Nikon D5000 and I'm starting to shoot in raw but I have photoshop cs2 and have downloaded the 3.7 update for raw plug-in but I still can't open raw images in photoshop. How can I get it to work?
If it will never work then please recommend some software that I could use to edit raw images but it as to be free.

Have you tried the latest versions of Camera Raw, my friend.

I don't know whether the later versions will work with Photoshop CS5, but see what information you can find from the following web page.