To save elements with a blank background in PSP, you will need to save it as a .png file.
After you have completed creating your element choose:
Make sure the following settings are the same:
Make sure the "16.7 Million Colors" is checked
Make sure the "Alpha Channel Transparency" is checked
and "Existing image or layer transparency"
Do not change any settings on the other tabs
Click OK or Enter than give your element a name and put it in the folder of your choice. Hit save.
Now you can use your element for your scrapbook layouts anytime!