DO I NEED CONVERTER BOX WITH NEW LG LCD HDTV?

I'm about to purchase a LG LCD HDTV. This will be my first flatscreen tv so the only thing i'd like to know is what do I do next to continue to get free channels on my new tv? Do I need a converter box for this as well or just an antenna? There is one I have my eye on that says built in ATSC, does that mean I will only have to purchase an antenna and do an auto scan on my tv? I live alone and really have no one to help me out with this so would appreciate all the help I can get on what I will need to do, thanks!