Yes, ORGANISER is a Scrabble word!

Letter values in Scrabble US: O 1, R 1, G 2, A 1, N 1, I 1, S 1, E 1, R 1.

Is it a valid word?

ORGANISER is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

someone who enlists workers to join a union
a person who brings order and organization to an enterprise
a lightweight consumer electronic device that looks like a hand-held computer but instead performs specific tasks; can serve as a diary or a personal database or a telephone or an alarm clock etc.

Also: labor organizer, personal digital assistant, personal organizer, personal organiser.

Not playable in Scrabble US: PDA.