The lightest mobile phone is the modu, which weighs 40.1 g (1.41 oz). It is manufactured by modu ltd. (Israel) and was launched at the Mobile World Congress in Barcelona, Spain on 11 February 2008.
The dimensions are as follows:
72.1 mm x 37.6 mm x 7.8 mm
The volume is 21.15 cubic centimetres
It has a full-colour screen and 1Gb of internal memory for music & photos