According to this press release, it sounds like medical centers are still struggling with finding effective policies about disclosing conflicts of interest (here's a link to the article about the study in the February 1006 edition of Academic Medicine). From the press release:
Among those institutions that do disclose this information to participants, there was considerable variation in the type of information and the way it is presented to potential research participants, found the researchers.
In their "snapshot" of how academic medical centers are managing the issue of conflicts of interest, the team sought to discover how much, if any, information about corporate sponsorship of clinical trials is reported to potential participants. They also said they hoped their study and others to come will help academic medical centers develop more effective conflict of interest disclosure policies.
Sounds like there's much more work still to be done in this area before we reach any sort of consensus, if that even is possible. (Thanks to Debra for the pointer!)