Soon the number of type Ia supernovae (SNe) measurements should surpass 10^5. 
Understanding weak lensing effects in these objects will then be more important 
than ever. Although SNe lensing is usually seen as a source of systematic noise 
in this talk I will show how this noise can be in fact turned into signal. 
I will thus first describe how we were able to accurately model the lensing 
effects. I will then use these fits to show that the SNe Hubble diagram 
dispersion is basically modulated by Omega_m0 and sigma_8. I will argue that 
the modelling of this dispersion allows for an independent measurement also of 
sigma_8 with supernova data. I will finally show some results using real data.