JCuda 0.4.0RC2 has been uploaded, intended for CUDA 4.0RC2.
This version is a release candidate. Some internals have been refactored, and the new features of CUDA 4.0 (e.g. unified addressing and peer operations) could not yet be tested.
The new API of CUBLAS (aka "CUBLAS2") is not yet supported, but will be part of the final release.
Apart from the update to reflect the new API functions of CUDA 4.0, there have been several bugfixes. See the change log for details.