i also saw some tutorials filling the inside of the text with a gradient from black to transparent, to give the pressed text"bottom" a sort of shadow

So I've followed the basic of the bump map idea just inverted the colours for the pressed text.
Then added the internal drop shadow for the pressed text and the external shadow for the embossed text.
Finally just to enhance the effect I made the colour of the inside of the text, not the bumped part, slightly darker than the main colour of the image for the pressed text and slightly lightly for the embossed text.



And with the provided texture, did create a grey scale image of text and displace the texture.

Love the purples

For a little more realism, you can run a displacement on the texture too, that will make it look like it's hugging the divets and bumps better.

I have another tutorial here you can check out.
http://gimpchat.com/viewtopic.php?f=23&t=428

awesome he4rty, you nailed it !