The Twelve Apostles are located in southern Australia along the Great Ocean Road. These spectacular rock formations, which are made out of limestone, were formed due to the constant erosion from the c
rashing waves of the sea. There are now less than twelve rock formations remaining due to some of them falling apart, but the ten or so that are remaining are spectacular. The best time to see the Twelve Apostles is at sunset when the sun "turns" the rocks a lot of different shades of red! The Great Ocean Road is a road that runs along the southern coast of Australia. It also features the famous Bells Beach (surfing tournaments), and a lot of different wildlife that includes Kangaroos and Koalas!
You can get to the Twelve Apostles by leaving Melbourne on the Great Ocean Road, if you are coming south from Alice Springs, or coming east from Perth. I know that leaving from Melbourne there are a lot of group tours that leave from hostels. All you need to do to join up with a group tour is talk to your hostel (in downtown Melbourne or in St. Kilda) and pay them the required money and that will register you for the tour. These group 
tours are generally 2-3 days, and are a great way to meet other travelers if you are traveling by yourself.
The other option is to rent a car, and travel the Great Ocean Road by yourself! This is probably the best idea, because you get to do the trip on your own pace. There are a lot of little beach towns that you can stop at for the day or stop to eat something along the way. When you are on the group tour you are not able to do this since you are on the tour guides schedule! If you are traveling by yourself there is still a possibility that you can rent a car with other travelers. You need to post a sign at the hostel that you are looking to meet up with somebody that is traveling the Great Ocean Road. You just will have to be patient until somebody contacts you or until you meet somebody.
Once you arrive at the entrance of the Twelve Apostles you are able to walk around different paths. There is also a helicopter tour that costs about $90 US Dollars. This tour gives you a once in a life time view of the Twelve Apostles. If you decide to skip the helicopter tour you can still see great views. There is a path that allows you to walk up and down the coast to see different views of the rock formations!
A little bit further down the road there is another rock formation that is not apart of the Twelve 
Apostles, but it is just as famous. The formation is called London Bridge. This rock formation actually looks like a bridge that is standing in the water! There are bits and pieces of this formation that are starting to fall down!
