If you want a hosted Cloud Foundry, my employers run one in Pivotal Web Services[0], aka PWS, aka p-dubs.
IBM BlueMix includes a CF instance. There's also AppFog and AnyNines.
Naturally, I think ours is the best. It's usually the most up-to-date, based on the internal monitoring I've seen. We upgrade PWS to the latest Cloud Foundry release usually within a week of one being tagged.
My favourite part about it is that thanks to BOSH, basically nobody ever notices that we upgraded the entire platform underneath them.
You can certainly host it yourself on AWS, GCP, Azure etc.
The general services administration is restricted to only assist federal government agencies, so you wouldn't be able to use the version being managed for the federal government.
