I really like this girl in college but she's had a boyfriend for about a year, I think. I don't know a lot about the boyfriend, although I've met him once.

We've become closer over the past few months and we do talk a good bit. On a few occasions we've slept (not made love) together in a bed after a night out and cuddled,etc. Almost kissing once as well.

I've been with other girls in college but I just cannot stop thinking about her.

I just don't know what to do. Should I tell her how I feel or just let it go??

Don't be that other guy. You do not want to be the guy she cheated with no matter how strong your feelings are for her.
If you were dating her, you wouldn't want her doing the things she did with you with someone else would you?
Don't cross the line until she and her boyfriend officially break-up. For your sake, hers, and her boyfriend.
Your actions don't affect you and you alone but other people as well.

Call me old fashioned LOL but I am not sure why a girl who is spoken for is sleeping in a bed and almost kissing someone else? Maybe its time to inject a little more honor into this situation and if that means putting your cards on the table, then by all means do so... but don't expect just because you do, she will. She sounds kind of confused to me and not taking other people's feelings into account very well, you know?

Everything that Val said and... How do you know whether you could trust her if she was with you.
If she has a BF and is snuggling with you... she could possibly date you, but go off snuggling with some other guy...

I would say, keep on talking to her but don't disclose your feelings yet.

It seems like something's not OK in her relationship with the other guy. Yet, is this a reason for her to be "almost kissing" you? I'm not sure...

You have to ask yourself if a girl that sleeps in a bed with another guy when she has a boyfriend is a desirable target when it comes to a girlfriend.

If so proceed with caution and let her know how you feel.

But I wouldn't expect anything if I were you. After all she does have a BOYFRIEND!

If she slepted with you and has a boyfriend, I think wait a few weeks then say you love her etc and then say something like don't cheat on me or something like that but be nice about it or she would want to be with you because you don't trust her or something like that.