hm, the picture is pretty small
it looks a bit like a bevel
there is a filter for that, when you go to Filters -> Decoration
another easier method is presented in this tutorial
http://www.youtube.com/watch?v=8LmW5ndn ... 0CE8219376its just shrinking or growing selections and filling them on seperate layers with different colors
how much depends on various factors: text size, desired effect, etc.
just try different values, you can always undo what you've done ('Edit' -> 'Undo' or Strg + Z, or go the the 'History Tab')
does that help ?