i remember designing, these types of logos a few years ago...
start with a basic outline, then grab it, paste a copy slighty up and left (per letter if you like), then shade in the top and left sections (try a light colour), then shade bottom and right sections (try a fairly dark colour), then pick a shade of the same colour between the light and dark, add this to the middle section.
you should now have a fairly 3d looking logo, blend the edges, then re-define, the edges, try using anti-alaising etc..
if i looks ugly in the early stages, try not to UNDO, go with it.
for a very quick start, choose a font, then add a bit of styling, then shade in, this will give you a idea of how to define light sources.
DON'T EXPECT MUCH IN THE FIRST FIVE MINUTES, if you look at the image you attached, and think, god my design looks crap, just keep editing until you find the style you imagine.
i'll knock up an image soon,