I'll talk about both, to start.
Sasusaku side, in my opinion is not likely at all. Sakura *did* love Sasuke in part one. It started out as a weakly structured crush, where the only reasons she liked him were for his looks and demeanor, to a somewhat genuine infatuation, and then into love. In episode 109, Sakura was desperately pleading for Sasuke to not leave the village, saying how she loved him and would make every day a joy. She even asked him to take her with her. But he simply gave a small "thank you" and left her on a bench.
In shippuuden, Sakura seems to be less interested in Sasuke, even expressing some resentment for him, an example where Kakashi transformed into Sasuke, and Sakura gave a hard glare. Another instance is shown here, in this manga page:
http://i201.photobucket.com/albums/aa139/bloodcream89/naruto/5868.jpg?t=1206682635 Sakura remembered first her words to Naruto, to help get Sasuke back, rather than a memory of Sasuke or such.
Narusaku in my opnion, is VERY likely. Naruto did have a large crush on Sakura in part one. As the story progesses, Naruto saves Sakura time after time after time, comforting her in her time of need, and Sakura realises in episode 110 that Naruto does relate to her feelings. Sakura does seem aware of this crush, not returning his feelings, but sometimes gives little hints that she accepts his feelings, like in the beginning of Shippuuden, she asks Naruto if she looked more womanly. Of course, naruto's stupidity kicked in, and he earned a punch.
Another 'Narusaku moment' is the Yamoto 'speech' where Yamoto tells Sakura that it does not matter what she does for Naruto, but how she feels, and how she truely loves (likes?) Naruto. Of course, he is cut off at the l- when Naruto wakes. Tears spring to Sakura's eyes, for she is joyous for Naruto. AGAIN, Naruto's stupidity kicks in, and he gets another punch.
Anyone see the obvious future? No? I'll spell it out.
As Naruto matures, his slip ups and stupid comments will slowly subside, and Sakura will grow fonder and fonder of him, becoming romantically involved.
There is further proof. The three sannin theme: Jiraiya is like Naruto, Tsunade is like Sakura, and Orochimaru...is unfortunately like Sasuke. Tsunade confessed her love for Jiraiya shortly after he died.
Plug in Sakura as Tsunade, Naruto as Jiraiya, minus the death (Naruto is the main character!). Why can you do this? Because history tends to repeat itself, or rather, very often.
--Flonnechann