Service Included is Phoebe Damrosch's dishy account of waitressing at Per Se, Thomas Keller's stratospherically expensive Manhattan restaurant. Both a sparkling stylist and the sassy heroine of her own narrative, Damrosch balances the sweet (her romance with a sommelier) and the tart (''More people throw up in the dining room of Per Se than your average college bar'') in a fun, if slightly tame, exposé. As in all these memoirs, the food is tantalizing, but what keeps you at Damrosch's table is the writing. A-