By adopting an open access policy for research articles, BMJ Open follows in the footsteps of the BMJ itself. All research articles published in the BMJ are available open access, a policy that dates from 1998. A recent editorial in the BMJ talks about the launch of BMJ Open and the BMJ‘s new policy on open access charges.
One of the editorial’s authors, and BMJ deputy editor, Dr Trish Groves has also opened the issue up for discussion on doc2doc here.