It doesn't seem like its different people from Heroku. If you've seen Mark Benioff's cloudforce pitch (link below), he mentions that they're partnering with VMWare to launch a PaaS similar to Heroku (which they acquired in December).
That said, I think its a bit surprising that VMWare is launching this under their branding - the machinations of large corporations continuously confound me.
"Cloud Foundry serves as the basis for the VMforce platform cloud VMware is building in tandem with Salesforce.com. Therefore, Chen tells us, developers will be able to readily move applications between VMforce and other Cloud Foundry services"
So they are both apparently releasing differently branded versions of the same stack.
There is no history in the git repos, so not clear if any of the code comes from Heroku.
That said, I think its a bit surprising that VMWare is launching this under their branding - the machinations of large corporations continuously confound me.
http://www.salesforce.com/video/cloud2011-nyc.jsp