Auto Left to right Pan

I need an auto pan that will pan left to right ever 2 or 4 bars. this one I have works very crappy and cheesey.

any direct X plug-ins? u recommend?

There's actualy a good one in Fruity loops believe it ir not, or you could do it manualy in pro tools or sumthin?

Not sure what program you're using but you could just use automation.