Fire up PSP and open up the image you want to turn into a mask.

When it's opened up, you will only have a small selection of colours available in the colour palette - a few variations of black and white.  PSP needs to have all the colours available before it'll let you do most things for some bizarre reason, so we need to go to the File menu, then down to Increase Colour Depth and across to 16 Million Colours:

Now that we've done what PSP wants us to do, it's time for PSP to return the favour!  :o)

We need to let PSP know that we want to make a new mask from this picture, so go to the "Masks" menu, down to "New" and across to "From Image"

A small dialogue box will come up with a few different options in it.  Use these settings for your mask then hit OK

Source window:  This Window
Create mask from:  Source luminance
Invert mask data:  unchecked

You'll notice that all the black bits of your image have gone now.  That's cool... this is PSP's way of showing you what the mask will look like when you've applied it to your picture - the white areas are the bits of your picture that will be left and the black bits are the areas of your picture that the mask will take away. 

Now we need to let PSP know that we want to save this mask on our computer to use on our pictures, so go back to the "Masks" menu, then down to "Save To Disk"

A dialogue box has now popped up asking you about where you want to save your mask and what you want to call it.  If it's not already pointing to it, use the drop-down box at the top to navigate to the Masks folder within your PSP directory - this is usually in c:/Programme Files/Jasc Software/PaintShop Pro/Masks.  

When you've got it pointing to the right directory, give your mask a name - I'm going to call mine WhispyOval (just 'cos I can't think of any other name for it!  lol) 

In the drop-down box underneath where you name your mask, make sure that it's got the extension of .msk - PSP should have automatically put it in for you, but it's always better to be safe than sorry :o)

When you've got all that sorted, hit "Save"

Congratulations!  You've just made your first mask from a black and white image!!  You might want to test it out to make sure of what it looks like... if you're not sure how to use a mask, follow this tutorial.