Paul Ramsey caught my eye last week when he posted the following:
ESRI will be participating in FOSS4G 2007 as a silver sponsor! This is a great chance for ESRI to articulate some kind of framework for co-existence with open source alternatives, and for the open source community to educate ESRI on the options for interoperability.
Go ahead and read his post as I think his thoughts on how ESRI might start a relationship with the open source community.