Prime Minister Harper is visiting the Western Wall in Jerusalem. Previous Canadian official visits avoided the Western Wall as Canada (officially) does not recognize Israel's claim to Jerusalem as capital (or sovereignty in general).
It is also significant that Prime Minister Harper will be speaking to the Knesset. This action implicitly recognizes Jerusalem as the Israeli capital (although the Knesset is on territory held by Israel prior to 1967 it is located in Jerusalem as Israel's capital).
Remember a previous Conservative Prime Minister, Joe Clark, planned to move Canada's embassy to Jerusalem.
Perhaps the Canadian official position will change? Maybe this change will be announced during the visit to Israel? If so this would be a very significant shift in Canadian policy.