What you exactly want to have?
Forum like Bitcointalk, or clone with all comments?
There is no big secret, this forum uses well known open source SMF forum script
http://www.simplemachines.org Download it from there, probably you can find many guides on how to install it.
As I know, forum admins make many improvements here, so I guess it not possible to have an identical fully functional website like this. If you want to have everything with all posts from here, there you need some programming skills, or you need to pay someone to create it for you.
Here are few people who are already doing scratching all posts because of different statistics, but you can't expect from them to make a copy for you because your request sounds very fishy and you can use these scripts to stole password from users.
