This one is quite simple but you can play around with it for hours. Start a new RGB image with a black background and white foreground. Type in some text. Now if you are using Photoshop 4.0, you must merge this type layer down by pressing Ctrl-E (or Cmd-E on Mac).
We will need one extra channel, so you should open the channel palette (Window >Show Channels) and drag any of the existing channels to the New Channel icon.
Now remove the marque by clicking type tool once again (don't type anything). Then use gaussian blur (Filter /Blur /Gaussian Blur) with setting 1.0 or 2.0
Now Filter /Other /Offset... 2,2. You will play with those values later. Then Select/Load Selection.... Ok, now you just adjust levels of the selection. Go to Image /Adjust /Levels... and play with it (make it darker this time).
This is nothing complex. But there are tons of variations you can do such as, inverting the image, inverting the selection, fill the type with a texture and so on.