Texting someone in another state?

I have AT&T and an iPhone with unlimited texting. If I text a friend who's gone down south for vacation (but still in the US) will it charge me extra or pop up on my bill or anything or will it be like any other text and not show up on the bill?

As long as you have unlimited texting, it applies to signals/phones within the United States. I text all the time with people not in my state and there are no additional charges.