In this post, Anthony Wells of YouGov shows that support for the alternative vote (AV) is now running neck and neck with the current, first past the post (FPTP) system in YouGov polling. This follows a period of four months in which FPTP was in the lead. Wells shows how Lib Dem voters have firmed up in their support for AV and Conservative voters' opposition has softened.
One group he doesn't comment on is Labour supporters whom, I believe, will be critical in determining the result of the AV referendum. They still prefer FPTP, by a 44% to 37% margin, down slightly from the 12% margin last October.