The Supercharger patents are indeed available for use, but with some conditions.
Tesla has said they will only allow Supercharger use on vehicles with at least 200 miles of range that are capable of accepting the full power of the Supercharger (they can't, for example, be neutered for cars with lower power limits). Also, the charging must be remain free to the end-user. The user of the patent is also expected to contribute to Supercharger network expansion in a manner proportional to their expected use of it.
I believe the no-cost-per-charge thing will give many potential partners pause, especially if they represent for-profit charge networks. However, these conditions are a good thing because, while they may slow down non-Tesla Supercharger deployment, they will also prevent the existing network from becoming clogged with slow-charging, low-range vehicles.