Pubget allows you to share papers with others who have access, so you don't have to go through the trouble of mailing them. Click on the result you want to share, then click email. This will email a link to the PDF. If you want to mail the actual PDF, read on.
Adobe Acrobat Reader (Mac and PC): Click on the email icon in the viewer's menu bar:
If your toolbar's missing this icon, control-click or right-click somewhere on the toolbar, scroll down to More Tools..., and add it. You may be prompted with an option to send a copy of the PDF or just send a link. Send the PDF.
Safari PDF viewer (Mac): If you're using Safari's PDF viewer on a Mac and use OS X Mail as your mail client, control-click on the PDF and select Print Frame... (not Print Window...). In the resulting dialog box, click on the PDF button in the lower left-hand corner, and select Mail PDF.
If you don't use the OS X Mail client, save the PDF and attach it to your email as you would any other attachment.
Schubert|it PDF viewer (Mac): Save the PDF and attach it to your email as you would any other attachment.