The Mobile Barcoder add-on for Firefox browser makes it easy to generate a QR code for the page URL, any link on the page, or if you select text, the QR image can deliver that also. If your school doesn’t have Firefox and the Mobile Barcoder add-on installed on public PCs, you could… install a portable version of the Firefox browser on a USB stick, and install the add-on there. That way, you have “your” Firefox browser, with any add-ons you might like, and your bookmarks also, wherever you go.
Then, if you are giving a presentation, and can project your browser window to your audience, or students, Mobile Barcoder makes it easy to push any links out to their devices.
Mobile Barcoder Add-on for Firefox (Flickr Slideshow)
NOTE: I used a screen capture utility called LightScreen to make these captures. Other screen capture utilities I have used did not allow me to keep some of the MB menus open after pressing on the Alt key, as part of my Hot Key setup for LightScreen.