Bridal Shower And Bachlorette Party

My friend is getting married in August of 2006. I was choosen as the maid of honor, which i know holds a lot of responsiblilties. My question is am I responsible for throwing a bridal shower and a bachloertte party?? I thought the mother was suppose to throw the bridal shower?? The bachletrtte party is expensice enough!!!And if so, what would be the best way of planning both of parties on a VERY limited budget???