1. Create a new transparent image and render some text using the text tool.

2. With the text layer selected, choose "Layer -> Transparency -> Alpha to Selection" from the right click menu, you should see 'marching ants' around your selection.

3. Grow the selection by 3 pixels using "Select -> Grow" from the right click menu, create a new transparent layer, positioned below your text in the layer stack, and fill it with your chosen glow colour, i've opted for #fffcd3 here, using either the bucket fill tool, or by selecting "fill with FG colour" from the edit menu.

4. Blur the glow layer by 6px using "Filters -> Blur -> Gaussian blur(IIR)" from the menu. To see the full effect of a light coloured blur you can fill the background layer with black for contrast. At this point you should have a glow which resembles that shown below, you can stop at this point, or follow step 5 to add an internal glow to your text.

5. Use alpha to selection, as in step 2, to create a selection from your text layer. Feather the selection by 3px using "select -> feather", now ensure that the text layer is selected and that keep transparency is unchecked and use "Edit -> Clear" to hollow out the centre of the black area.