Center of an image

Is there a simple way of adding a horizontal and vertical guide to show the center of an image?Center of an image
When you create the guides type in 50% for the horizontal and vertical values.Center of an image
Great.

Thanks
This can be made into an Action as well and tied to an F key combo.
Grab these actions:

http://home.comcast.net/~phoz/bbs/GuidelinesActions.atn

ADDENDUM/CAUTION: I seem to remember something about the ''TicTacToe'' action in that set being inaccurate, so you may want to ditch it. Gotta save the new version out of Photoshop and upload it to my server space. I'll have to do that later...

kind of bad acne