Hey! So I searched for a good tutorial showing how to create the text effect, and I wasn't too impressed with some of 'em So in a nutshell, here's what you do:
1.) In Photoshop, select the text you want to apply this to, and open the "Layer Styles" panel.
2.) In the panel, select "Drop Shadow," and change the properties to the following: - White, "Normal" Blend Mode, about 65% Opacity, 1px Distance, 0px Size. (This is what makes the white "edge" shadow).
3.) Then select "Inner Shadow," and do the same process as before, only use Black instead of White, and if you want, increase "Size" to whatever looks good.
Hope this helped! PM me if you need a PSD version for your own icons. Good luck!