Frankly - do it in photoshop and then use the combined image as the background for your text box.
It depends if the photo is intended to fill the entire text box or if it is a "global" background with text over top.
If the former, do what Franko suggested - combine your overlay with the image into a single image, or create a semi-transparent PNG of the image.
If the latter, create a small semi-transparent PNG for the overlay, and let it tile inside the text box so it adjusts to whatever size of text/table/region you want.
sounds cool = not sure how to make that in PS - will play with that a bit and report backcreate a small semi-transparent PNG for the overlay