Sigh.... let me deal with the issue maturely before the BNP lot come out:
Homosexuality is not acceptable in Islam. No we don't go around beating gays up.
However, you cannot be a true muslim and practising gay at the same time. The actual act sexual intercourse between men is forbidden as opposed to homosexuality.
There's nothing in the Qur'an that stipulates the punishment of homosexuals but certain Hadiths (sayings of the Prophet) have a very strict punishment on it- imprisonment, exile and even a death penalty. Yeah it does seem a bit harsh in today's society but the Hadiths aren't meant to be timeless (they might not even be authentic).