STEP 1:
Make a new image with a white background (Ctrl + N) with the following attributes:
  Width: 41 pixels
  Height: 14 pixels

STEP 2:
Zoom in. Draw a black border using the paintbrush (square.1pixel)

STEP 3:
Fill in the boxes with a color. I used purple.

STEP 4:
Now using the paintbrush (square.1pixel) write in text.

STEP 5:
Choose a lighter color and fill in the inside left + bottom lines:

STEP 6:
Now choose a darker color and fill in the inside top + right lines:

STEP 7:
Save that image. With a different color fill in the first letter and save. Do the same for the rest of the letters and one for all of the letters.

STEP 8:
Make each image you saved transparent. Go to Colors > Select Palette Transparency. Use 'Optimized Octree' and 'Error Diffusion'. Make sure the color you want transparent is the background.

STEP 9:
Open up Animation Shop or any animation program. Select it to be played 'indefinately' and set each frame to be displayed 25/100 seconds. When done it should look like: