The difference is One Way Anova is a single Factor and a Two Way Anova is two Factors.
http://answers.yahoo.com/question/index?qid=201206...

One way anova has one independent categorical variable, and asks if there is a difference between the groups defined by that variable. Two way anova has two independent categorical
http://uk.answers.yahoo.com/question/index?qid=200...

A OneWay anova is a way to test the equality of three or more mean...
http://www.chacha.com/question/whatisthediffere...
