Seeing multiple sources announcing this. Supposedly, Trump will have a call with Benjamin Netanyahu today and make the official announcement sometime tomorrow:

Reports @POTUS will tomorrow announce US Embassy in Israel WILL move from Tel Aviv to Jerusalem. Phone conference with Netanyahu today — Kay Burley (@KayBurley) January 22, 2017

BREAKING: President of the United States Donald Trump will announce tomorrow move of the U.S. embassy to Jerusalem – (Channel 2). — Israel News Feed (@IsraelHatzolah) January 22, 2017

A poster is in Jerusalem celebrating the move (though this may have been up before and was wishful thinking at the time)

Giant Jerusalem poster thanks Trump for embassy move https://t.co/bQQ7LssA6H via @timesofisrael — Ladieanne (@ladieann) January 22, 2017

More to come as this news continues to break.