From this Vita Nuova page you can download a free version of Inferno or order one of the commercial distributions. A plug-in version for Web browsers is also available.

Inferno source code made available under a liberal, low cost subscription plan.

They provide Inferno support in Japanese.

This was the original Inferno mailing list.

Inferno: The OS for distributed applications on network devices. Lead distributor for Inferno and Plan 9 OSs.