I have been reading about them in some of the posts and everybody seems to think they are the coolest/best, so please how too join them? (And yes, i have done a search but it didnt show how to join them)

1. Join Godsmen.

2. Find Bedai-Lihn in Godsmen Foundry - and tell her what she wants to hear.

You'll get some quests...

go around yelling DOWN WITH THE GOVERNMENT


that will work

POSSIBLE SPOILER
*
*
*
*
*
*
*
*
*
*
*
When you get that second quest to join the Anarchists, Bedai-Lihn says that the guards won't notice any more noise than usual

Of course, when I go to kill him the guards attack as well and the whole damn Godsmen faction tries to kill me when I get downstairs...

Is there any way to stop the guards noticing that you're trying to kill the factorum?

I just closed the door before killing him and all went fine.