Here's a handy airgun zeroing target that you can print off at home and use to get your scope zeroed. It's calculated for 25 yards range, but can be used at other ranges.
Update: I've now worked out how to allow access to the full-size version of this file on flickr - just click the image above then choose to dowload the 'original' size.
What other targets would you like to see here? No promises, but let me know and I'll see what I can do.