Many people use phpBB,Invision Power Board to make english forum.

But did you hear about on Discuz??

I am Hong Kong people and i can tell you about that.

Discuz is created by mainland China.
Many people use it for chinese forum.
It is freeware but of course you can apply for business version.
Since it is free of charge, peolpe can improve it togeter.

I think Discuz is more powerful than phpBB and Invision Power Board.
Because it have many functions such as ,Devil system, pet center,game centre, court,etc..etc........
It also have many styles to display.

Unfortunately, Discuz only have simplified chinese and tradditional chinese verions.
I hope there will have english version later.
It's really great!!~

Just for sharing my feelings only.