Bike to bike communication suggestions

[jmax5105]

Just picked up my new '08 Nomad the other day and am really liking it so far. I guess it's time for my first question to the forum. I did search for this topic and didn't find much so if any of you know of somewhere in the forum this has been asked, let me know.... if not, here goes! My dad has an '07 Goldwing (pretty much every option you can imagine) and now I've got my Nomad, I'm going to need to keep tabs on him when we go on some longer rides and will need to communicate with him. I don't anticipate being too far apart at any given time but wanted to know what suggestions you all had for bike to bike communication. I know I'll need a new helmet as well, so let's just say that I don't have anything other than the bike to start with. What would be the easiest (and hopefully not too expensive) way to get started with this?