Yes, I spotted Gossip Girl's Jessica Szohr out and about during New York Fashion Week with a mid length bob. Even though I caught glimpse of her before Herve Leger, she also attended several other shows like Marchesa and I got the 411 on her bob transformations from Pureology Colour Ambassador, Ruth Roche, who worked with Jessica throughout the week. "Since Jessica still has some length to her bob it leaves her with a lot of styling options," commented Roche.
To achieve smooth bob (as seen at Herve Leger), all Roche did was blow dry Jessica's hair with a round brush, but shine serum was the key to creating smoothness and adding a bit of separation. She used Pureology Colour Stylist Cuticle Polisher. I use this too and just place a small amount in my hands, rub them together to warm it up (so it distributes well) and then rub on my ends for added smoothness.
To get a more texturized look like the style Jessica rocked at the Marchesa show, Roche blow dried her hair and then used a 1 1/2 inch curling iron to randomly curl sections of her hair inwards and outwards. The trick to this 'do was to leave the iron in longer on some sections than others and pulling other curls out a bit so the curls were all different. In the end, the loose waves were texturized with a lot of movement.