Go to
www.chinesepod.com (or look for Chineses in itunes podcasts) you can download tons of lessons for free and get tons of other stuff on the website for $$$....all I can say about chinesepod is...na ge dongxi hen how (yes I know its crude but whatever)...just throw the lessons onto a CD or your ipod and practice/practice/practice
I have taken classes and wouldn't recommend the ones I took since they focused heavily on character recongition...I just wanted to learn how to speak Mandarin for survival