For now you'll need rust installed, see rustup.
In case you have fresh installation of rustup
you might need to do:
rustup install stable
$ cargo install --git https://github.com/aiken-lang/aiken.git
$ aiken --help
For more information please see the user manual.
Aiken defines its roadmap using Github Milestones. The roadmap isn't set in stone, but gives a high-level overview of where the project is headed for.
Want to contribute? See CONTRIBUTING.md to know how.
Note
The name comes from Howard Aiken, an American physicist and a pioneer in computing.