Ya, all their info should be on their site somewhere.
They do charge for exchanging currency like jsaw said. Its done fairly as far as I can tell.
I do know that they charge fees for transferring money from one MB account to another but its minimal.
I find that MB and other sites similar to it make depositing and withdrawing really easy when dealing with poker sites
because you always have to have made a deposit with the method that you want to withdraw. I have the same MB account for all pokersites now and it super easy to move money around.