Yes. Visit the Print Lessons page on the website. From here you'll be able to find any song you've purchased under your account. When you click "Print" on the right hand side, it'll bring up the .PDF for the song in a new window.
In the Safari browser, click the actions button (a square with an up arrow), which prompts a list of in-browser commands. Scroll through the options until you see "Print" and click that. If you have a wireless / WiFi enabled printer that is connected to the same network as your iPad or iPhone, then the printer should appear under "Select Printer...". If it doesn't appear, consider checking the network settings on both devices. Please note that you must use Safari for the print function to appear. Other browsers may cause problems.