Rezoning from Residential to Commercial

Hi,

Im currently looking at a residential property on a main road. There is a proposal to rezone the street from residential to commercial. I think some houses in the street have already been rezoned, and this is a split level home where the top level is being rented out seperately to the bottom level (which I think is being used for home business purposes). Im just wondering if anyone knows if the re-zoning will affect the value of the property at all? Has anyone been in this situation before? Any comments would be great.

Cheers,
Ben