Here are some resources for beginning Tango dancers:
General Milonga Etiquette
This PDF document will help new dancers understand the etiquette expected at Milongas. A Milonga is a Tango dance party where the Tango community gets together to dance socially.
Dance Floor Etiquette
This PDF document explains the skills that it takes to dance on a crowded dance floor at a Milonga.
Tango_GA Yahoo Group
Great place to learn about everything Tango in Atlanta. This Yahoo group is used by all of the Atlanta Tango Organizers and the calendar has every class, milonga and practica listed on it.