WAP (Wireless Application Protocol):

It is a method of letting a wireless device, usually a mobile phone, view Internet pages, using text only, and very simple black and white pictures.

The web site has to be specially designed for the WAP phone, and the pages have to be fairly small as the data speed on mobile phones is a lot slower than on domestic modems. Also, all the phones will have screens of different shapes and sizes, so pages will look different depending on the phone your are using.