You can download the source tarballs here. The releases are signed with the gpg key (F33E3FC6), which you can find here or on any keyserver.
openSUSE and Fedora
RPM packages for openSUSE, SUSE Linux Enterprise and Fedora are available here.
A NSIS installer of the latest version can be found here. The packages are created in the openSUSE Build Service and available as RPM packages here.
You can get the latest version of the master branch as zip and tgz.
You can get the latest version of the v0-4 branch as zip and tgz.
git clone git://git.libssh.org/projects/libssh.git libssh
git clone http://git.libssh.org/projects/libssh.git libssh
To start with git take a look at the Git Community Book.
You can browse it here and here.