When i first came across this thread, i was shocked... because i believed i'm in the same type of situation, except that i'll be B... For a while there, i thought icyprincess may be the girl i like until i saw her profile.
My situation will be almost exactly similar to B's. I came to like one of my female classmates and we became quite close, smsing, chatting online at night or on the phone every day. I then decided to get along with chasing her. I started asking her out solo, instead of with a whole group of friends. The response then was favourable, or so i thought. I knew she had a breakup fairly recently in December though. I bought her a present when i went on holiday. I made a point of remembering little details about her, such as her favourite drinks, food, her behaviour. It seemed to surprised her when she came to knew i was observing her but i thought then that she was pleased. I was quite obvious about my feelings through, even though i never said that i like her out loud. Our exams was at the end of last month and i've already decided a while back to ask her out after the exams and told her about my feelings face to face (i've always believed that it's better to say these words face to face rather than through the phone). I've even asked around for romantic spots to do this.
Unfortunately, as we neared the exams, how she behaved towards me seemed to have changed. When i asked her out a few times, she always said she was busy. I thought that it could be the exams bothering her, though at the back of my mind, i wondered whether it could have been her relationship problems came back to bother her. But i still decided to go ahead with my original idea, since i did not like to beat around the bush (plus she had once long ago made an off-hand remark that guys should expressed their feelings if they like someone).
So after the exams, i asked her out the very next day. She again said she was not free. And so on for the next day. Then, i met her online on msn. Her words were very... stiff, not like all the previous times when we chat. Then she made a remark. "Do u believe in out of sight, out of mind?"
I knew something was bothering her. I asked her whether i can meet up with her. Her reply broke my heart. "No, i do not want to meet u". I tried to chat a bit of other things with her but my heart wasn't into it, and i finally made an excuse and disconnected from the chat.
That was then. From then until today, she did not smsed or called me, nor did she came online. It was a far cry from before, when hardly a day went by without contact. I did not attempted to make any form of contact myself, hoping everyday that she would call, that her words "out of sight, out of mind" was not meant for me to stop contacting her and put her out of my mind. But nothing so far...
I'm still feeling upset. It was not because she rejected me, since she has every right to do so and towards the exams, i was already bracing myself in case of a rejection. It was because this happened just when i was about to tell her that made it unbearable.

Maybe that's why i'm writing out my story here. As i read icyprincess's story, i'm beginning to realise that maybe, i was in B's exact same shoes.
Icyprincess, i've always believed that girls are very perceptive creatures. If B really likes u, u will know and sense it. He may be in my shoes, trying to find a suitable time to express it. If u decided not to accept him, be nice in the rejection, don't just ignore him like u said u might do. It's better for him to know your true feelings, rather than letting him wonder what had happened to make u suddenly ignore him. If he had been nice to u, he at least deserved that. Take care.