ok, you guys can all line up and slap the (****) out of me later but I need help at the moment.  I know this is one of the simplist things to do in photoshop but I have not done it in a while and for the life of me can't remember how to do it. 

I am working on a web header and have an image on the right side.  I want to do a fade out from right to left with the image fading into the left center of the background.  Again, I can remember how do do it.  can someone help my already stressed brain and tell how or point to a tut?  thanks.