I’m a new user from oscommerce too, but cs-cart can bulk import products, though I’m not sure how yet :). Hear it can’t import it with pictures though. Better to contact cs-cart directly if no one else replies (though usually they do).
Otherwise I’m still ‘modding’ cs-cart, but think it was worth every penny compared to the frustration of getting oscommerce to do exactly what you want it to do.
i was going to use oscommerce as well but came upon cscart before i started doing anything. use the help they are great. cs cart is worth the time