SINA is now an open source project.
The source code is availale at GitHub.
Binaries will follow, in the meantime you can find the latest binaries below.
Citation:
Pruesse, E, Peplies, J and Glöckner, FO (2012) SINA: accurate high-throughput multiple sequence alignment of ribosomal RNA genes. Bioinformatics, 28, 1823-1829