I am interested in purchasing an intercom system to use on my 2-up.  I am planning on using it only for communicating between myself and a passenger during trail rides.  I have read the comments on atv to atv communications.  Are the intercoms any better for driver to rider as opposed to atv to atv?  Also, are they radios or are they wired directly together.  Thanks a bunch for your suggestions and/or comments.  

If you won't be riding more than a few hundred feet apart  from each other a BlueTooth option is good. With it you don't have to worry about interference from other riders. It also has noise cancellation which will be important for ATV use. The one I recommend is at the website below. It is very popular and a good product.

http://www.intercomsonline.com/BlueAnt-Bluetooth-Motorcycle-Intercom-p/093747.htm