[R] One way ANOVA with NO model

[Jason Horn]

I'd like to do a simple one-way ANOVA comparing the means of 6  
groups.  But it seems like the only way to do an ANOVA in R is to  
specify some sort of model, where there is an outcome or dependent  
variable that is a function of independent variables (linear model).   
But I don't have a linear model, I just want to do a simple ANOVA  
(and f-test) to compare the means.  How do I do this?  My stats  
skills are basic, so please bear with me.

Thanks for any ideas...