• Add a Vector layer to your image (Layers menu, New Vector Layer)

• Click on the Text tool 

 Set up the materials pallet:

On your materials pallet, set both the foreground and background colours to be solid colours (Not gradients or patterns) and choose the colours your would like for your text.  The background colour will be the main colour and the foreground colour will be used for a line around the text.  If you don't want a line around the text, set the foreground colour to null.

• You can choose your colours from your image, by clicking the foreground and background colour swatches (not the rainbow) and then move over your image and select your colour with the dropper.

Create The Text:

You should already have the text tool selected.

• Click on your image roughly where you want your text to be.
   
• Enter you text in the Text Entry Box.  Highlight the text you have in the box (drag across it with the left mouse button held down).  

• Select a font from the pull down list 
   

• Set the size to 48 or 72
   

• If you have selected a foreground color, set the Stroke Width to 1 or 2, depending on how strong you want the line around the text to be. 
   

• Make sure anti-alias is ticked.

It doesn't matter if some of the text has disappeared off the edge of the image at this stage.

Position The Text:

Now we are going to move the text into place and adjust its size so that it fits just right.

• Click on the Object Selector tool (its the one that looks like , at the bottom of the Tool Pallet)
   
• You will see dotted lines around your text now with handles on the corner and a spot in the center.

• Point at the spot in the center and drag the text (hold down your mouse button) to where you want it.
   
• To adjust its size, drag the handles on the corners of the text in or out diagonally.  You can even squeeze your text width-ways a bit if you need to, to make it fit, without reducing the height.  Or stretch it without making it taller.

• Layer menu, Convert to Raster Layer (its near the bottom of the menu).

The following steps are optional - you could apply either effect, both or none.  Adding a Drop Shadow will help make your text more visible.  Giving text an Inner Bevel will make it look 3D.

Add an Inner Bevel :

• Effects menu, 3D Effects, Inner Bevel.   You can use the settings shown here or as a starting point and experiment.

If you want to save these settings as a preset, click the disk button next to the presets pull down list.   

Once it is saved you will be able to choose these settings by selecting the name you've given them from the Presets list.

To see the effect of the bevel on your image, before applying it, click the eye symbol.  Click it again each time you change a setting to see your image with or without the bevel applied.

Add A Drop Shadow:

The shadow makes the text really stand out.

• Click the Effects menu, 3D Effects, Drop Shadow

Use these settings:

Vertical=2, Horizontal=2, Opacity=50, Blur=6, Colour=Black

This is how the text should look when its finished.

• Layers, Merge All

Then Save as a .jpg file ready to share your results.