If you're a PHPFog user, you know that they're discontinuing the service in favor of their AppFog product. If you're looking to migrate over to this from PHPFog, you should check out this new article from PHPMaster.com with some of the differences between the two services.
Have you heard PHPFog is coming to an end? No, well - it is. That’s right, in a recent announcement on their mailing list, the company has said that PHPFog will be no more by the end of January, 2013. But if you’re on their platform, don’t panic! The new, combined platform may be even better than what you’re accustomed to with them now.
He talks about some of the things that are different including the technologies it employs, addons it provides, the differing deployment process and when teh final cut-off date is. He links to their own migration guide for most of the steps but mentions one specific change that might trip you up - the change to store connection information in the "VCAP_SERVICES" environment variable.