Immersion, which calls itself the "vibro-tactile technology expert", has developed technology that gives you the sensation of pressing a button when you push a virtual button on a touch-screen.

VibeTonz is an inexpensive and robust way of giving tactile confirmation that pressing the button was accepted as input.

Passive touchscreen technology usually results in more human error and frustration by the user, but the VibeTonz system heightens interactivity and makes virtual buttons feel more like mechanical keys.

The technology is relatively-low cost, so the hope is that PDA and mobile makers will integrate it into the latest devices, especially since screens are getting bigger, forcing mechanical keys to get smaller.

Stuart Robinson, director of Handset Component Technologies service at global research firm Strategy Analytics explains: "Touch screen technology in phones is primarily aimed at high-end smart phones and PDA's at present".

"The integration of any technology that enhances the user experience and improves ease of use will be important for market adoption."

The VibeTonz System has already been implemented in a number of ways. It has synchronised vibrations in ringtones to match the beat or melody or to vary according to caller ID.

Alerts can also be matched to certain vibrations – like a deep Big Ben toll, a tapping, or the rhythm of ocean waves – to make them more memorable.