ComputerBB

Hi, I'm looking for a few lines in an .htaccess file to do the following and include a 301 redirect

rewrite
"http://www.computerbb.org/ftopic(numvar).php"
to
"http://www.computerbb.org/about(numvar).html"

rewrite
"http://www.computerbb.org/sutra(numvar).php"
to
"http://www.computerbb.org/post-(numvar).html"

rewrite
"http://www.computerbb.org/forum(numvar).php"
to
"http://www.computerbb.org/forum-(numvar).html"