Advice from ROSPA
Passenger Airbag in Front of Car
It is safer to put children, including babies, in the rear of the car. Some parents prefer to put babies in the front so they can keep an eye on them. However, it is very dangerous to put a rearward-facing baby seat in the front if there is an airbag fitted on the passenger side. The baby seat will be very close to the dashboard and if the airbag went off it would strike the baby seat with considerable force.
It is not as dangerous to fit forward-facing seats in the front when there is an airbag present (although it is still better to put them in the rear), but make sure that the car seat is as far back as possible and the child seat is securely held to maximise the distance between the child and the airbag.
Solution
Fit rearward facing baby seats in the rear of the car. If you feel (for medical reasons, for instance) that the baby needs to be constantly monitored, find an adult to sit with the baby.
If you must put a forward-facing seat in the front when there is an airbag present (make sure that the car seat is as far back as possible and the child seat is securely held to maximise the distance between the child and the airbag.
It may be possible to have the passenger airbag de-activated or removed, although this means that any adult passenger sitting in the front will no longer have the extra protection offered by the airbag. Check with the car manufacturer and follow their advice.
I previously posted this in an august thread which had big discussion on this
www.mumsnet.com/Talk?topicid=9&threadid=33765#783128