Making desktop icons:
there are startscripts sage.sh, sagen.sh(html notebook) and sagedoc.sh in the /usr/sbin directory.
drag those to the desktop (Icons are in /usr/local/lib/X11/pixmaps)
I used the ready made version for ubuntu which can be downloaded from sagemath.org
This is a packed with lzma so
tar --lzma -xvf sage-*...tar.lzma
then the gfortran libraries were missing (they are included now in the sfs /usr/lib/) so get those. (You can also get them from the gfortran.pet)
After that you change into the sage directory and with ./sage the package is installed (paths are reworked).
I made the sfs (mksquashfs sage-directory output.sfs) before the first run, because then the package is a bit smaller.