Problm in web pages

hi
I am having a serious problem in my HTML pages while making tables. If there is a two columned layout and when i write some text in the left column the text in the right column goes down.the more the text written in the left side, the more the text goes down in the right side.
I have been taken some ideas from web site design company sites during net surfing but didn't sure.
If u got my problem,please solve this.