In PS, start a new file with a black background, size to 720 x 576 (Pal) or use NTSC dimension. The reason for this is so that you get an idea about what size it will be over video, however you can use any pixel dimension you like.

Type text on it or place a logo, (in case of a logo, use the erase tool to wipe out areas that you would like transparent)

Add a drop shadow

On the layer property palette, click new layer icon, this places a new empty layer above, this is necessary for the drop shadow to work

Turn off the bg layer so it looks like the image on the right

PS layer menu up top, choose merge visible

Now turn the background layer on again, this will ensure that the drop shadow will be black

PS select menu, choose load selection, click OK

PS select menu, choose save selection, click OK

PS file menu, choose save a copy, choose tga, type a name and click OK, choose 32 bit, click OK