jheem, I wouldn't say that they are almost the same. The colloquial versions of both have borrowed extensively from the other and are therefore rather similar. Same process of interweaving colloquial versions of Hindi and Marathi, has led to an altogether unique tongue - Bombay's lingua franca, 'Bambayya'! Shanks will certianly know more.

Urdu has a lot of Farsi in it and Hindi a lot of Sanskrit. I speak Hindi with some difficulty, but can comprehend it very well. I was listening the other day to a CD of ghazals (Urdu poetry set to music) of a famous poet, Mirza Ghalib and I can quite confidently say, I understood nary a thing!