How to become a Hindu
Before we begin, I think it's necessary to state that in mainstream, that is,
orthodox Hinduism, you
can't convert. If you're born outside Hinduism, you're screwed, no hope for you. The best you can do is follow the path of
dharma as much as possible and hope that in your next life you are born as a
Hindu. This is how to become a "real" Hindu. However, there are to my knowledge at least two "flavors" of Hinduism that will accept converts. Beware: most "real" Hindus (particularly those within
India) will not accept you as a real Hindu, and look upon you with mild (but generally benevolent) amusement. The two flavors that accept converts are the
Arya Samaj and the
Hare Krishnas (
Oolong informs me that while Hare Krishnas are in most aspects Hindu, some do not consider themselves to be; notably,
Swami Prabhupada disliked the word and did not consider the movement Hindu).
The Hare Krishnas' method of conversion seems to be fairly simple: love Krishna, chant the maha mantra, and follow the path of dharma (vegetarianism, ahimsa or non-violence, abstinence from drugs, gambling, sex except for procreation, etc.) The website (http://www.iskcon.org) doesn't say any more than this; however, I have seen Hare Krishna converts in the past wearing the janiwara, the thread that Hindus of certain Gotras (thanks rischi) wear after going through their upanayana (coming of age ceremony), when they are taught to do japa and pooja, so it is reasonable to assume that part of the complete conversion process is in fact going through an upanayana of sorts. Update: nine9 informs me that "yes, all Hare Krsnas eventually go through the upanayana, but as well as getting brahma-gayatri, which young boys get, we then get the other mantras for deity worship."
I have no idea about the Arya Samaj, as their website (http://www.aryasamaj.org) is in Hindi and I can't read it, so if anyone knows, write below. It is reasonable to assume that the Arya Samaj also require one to go through the upanayana.
The fact of the matter remains, however, that your best bet for attaining moksha (nirvana) is not to attach yourself to a group that contravenes vedic dogma, but to simple follow the path of dharma, accumulate good karma and pray that you will be born a Hindu in your next life.