Hi,
Attached is an Excel spreadsheet showing an examle of a 72 steps/cycle SIN table with an 8bit dutycycle. You can modify it for any number of steps and resolution you see fit or you may want to create one half cycle and then have your code invert it for the second half and so on - it's up to you.

To get three phases there's no need to have three tables, you use three pointers 120° appart indexing the same table. So, with the table in the attached .xls you start at steps 0, 24 and 48 respectively.

/Henrik.

EDIT: Crap, can't attach the .xls here. Send me a PM with your email adress and I'll send it to you.