First open the image you want to make into a scribble in PSP, I am going to this picture that I drew in flash earlier:
Now that you've got your image go to Layers and click on New Raster Layer then click OK.
Click on the brush tool and set your pen size to 1. Change the colour to the colour of the outline of your picture (mine is black).
Now draw over the out line of your image, dont worry if its messy, its supposed to be, after you've drawn around it 2 or 3 times it should look like this:
If you have any little lines in the middle of you scribble (like I have on the petals) then scrible over those like you just have done but make sure you select the right colour.
Once you've done that click on Raster 1 from the layers list (on the right) if you cant see Raster 1 click on the layer at the bottom of the list, then click the little eye next to it so its crossed out. Your original picture should disapear leaving the scribble copy there, this is just to make sure you haven't left out any lines.
If you have scribble over the lines (but make sure you click on Raster 2 before you do). If you scribble looks like this:
Then click on Raster 2 and fill in the center of your scribble and add any details. You can then save your finished scribble, I recomend outlining it in white if you're going to save it with a transparent background. Anyway heres my finished scribble:
