2 colums layout 100% height

hello, i need help understanding the 2 colums fluid layout,
i have a header, conatainer witch has a left div and a right div, and the las div is the footer.
i managed to make a 2 colums layout, i made them both 100% height, the problem that i have that if in the right div has much more content and streaches more then the left div, the left div`s height wont streatch too as the right`s div height, i cant manage to make it work at all, searched for tutorials about that but still failed, and a other problem that i have is that i cant make the width of the right div be 100% whitout droping under the left div, i used float for that. help, can someone give me an good example for a 2 colums fluid with 100%height, if u know a really good article about that, please give it to me, or a tutorial about that, i searched like an hour about this on google but i failed bigh time, cant find a good tutorial, all i found were css code and that was all, no explanation about it at all, please help