Colectivo from Pochutla will get you only to Puerto Angel. So if you are headed to some other beach (Mazunte, Zipolite...) you'll have to take a taxi. There are lots of them in Puerto Angel and all the drivers just long to take you to Bahias De Huatulco :-)
There really isn't much transportation in Puerto Angel. Once you get there, the town is pretty easy to walk around. Actually getting there however is another story.
there are flights from DF to Puerto Escondido (a popular surfing town just west of Puerto Angel) and there may be buses or combis linking the two.
I will find out more info and post.....