[R] x-axis tick mark labels running vertically

[Mohamed Abdolell]

I'm plotting obesity rates (y-axis) vs Public Health Unit (x-axis) for the 
province of Ontario and would like to have the Public Health Unit names appear 
vertically rather than the default, horizontally.

I'm actually using the 'barplot2' function in the {gregmisc} library ... I 
haven't been able to find a solution in either the barplot2 options or the 
general plotting options.

Any pointers would be appreciated.

- Mohamed