I would like to know how to get usd that i have in my MtGox to btc24?
Mt. Gox has ended its redeemable codes. The only withdraw methods are those listed on their site (e.g., bank transfer and OKPay).
Bitcoin-24 is currently down, so I'm not sure how you would do that anyway though (other than to buy bitcoins at Mt. Gox then sell bitcoins at Bitcoin-24).