You don't need permission at all. The only thing that Badspot actually owns on the forums is the logo at the top left of the screen.
EDIT: And it's a website. Anyone is free to access a public website.
DOUBLEEDIT:You make money for a free application?
Firstly thats my point the app would use the Blockland branding.
Also to ansewr your question on making money with a free application, I use iAds which is Apples mobile advertising network. It works quite well and definately the highest paying out of the others like Admob.
People see ad = I get a bit of money
They click ad = I get even more money
They complete or buy whatever the ad is = I get alot more money :D
