I am the creator / main developer of a small sized open source (PHP) project (GPL3). Currently there is a development team of 3 people (me included). This team has been quite active for some time, but since almost 2 years not much has happened. I myself have decided I want to stop working on the project, but I can't just leave the project because I care about it and I know if I abandon it, it will just be a matter of time before the project completely dies. At this moment, there are still some users and the project is only slightly out-of-date.

So I'm thinking about selling the whole project. Of course I'd need to get consent of the other developers, but for now I'm assuming that's not a big problem. So at this moment I have 2 questions:

1) If the project would be sold to a commercial party, would it be possible for them to convert the project to closed source? I would prefer to sell the project to a company/organization that would continue the development under an open source license.

2) Does anyone have any tips to find interested parties? I don't know if I just want to put up a "For Sale" sign on the website of the project. Maybe someone has experience with a comparable situation.

Ok guys, thanks in advance!