Ifbyphone's Click-to-Call module is available for download on Drupal.org. Click-to-Call enables website visitors to enter their phone number in a form, click a button, and call you. When they click on the "Click-to-Call", both your phone and their phone will ring and you'll be on the phone together.
Yes, it is possible to include multiple Click-to-Calls on one page. While the module allows for 1 click-to-call, via Ifbyphone's GUI you can configure up to 25 different click-to-calls and then simply embed the code on your website. Call Ifbyphone at 877-295-5100 with any questions.