Pulley Question: Clarifying Fnetx Calculation

[jesuslovesu]

http://img135.imageshack.us/img135/3314/yeaheg1.th.png

I was wondering if someone could clarify this for me.
(this system of accelerating, the block on the right is heavier)
I know that Fnetx = T.

However, I'm a little confused about why Fnety should be Fw - T as opposed to T - Fw

When I was doing the free body diagram, for the y coord: T points up and Fw points down, so I was thinking since the standard coord system has up as +y and down as -y then Fnety = T - Fw, unfortunately it seems that it's necessary to reverse that.

 

[BishopUser]

probably reversed so that acceleration comes out as a positive value for both blocks.