The leaders of the United States, the Palestinians and Israel have agreed to immediately launch peace talks with the goal of reaching a final accord by the end of 2008. US President George Bush made the announcement at the opening of a key Middle East peace conference - the first such summit in seven years. The agreement follows lengthy, last-minute negotiations between the parties on a joint document meant to chart the course for negotiating the toughest "final status" issues of the conflict -- Jerusalem, borders, security and the fate of Palestinian refugees.