This is a short post about installing Spatial Index on Ubuntu. First download the latest release. At the moment it's version 3.2 and cd to the location of your download. Then issue the following commands :
tar xzvf spatialindex-1.3.2.tar.gz cd spatialindex-1.3.2 ./configure sudo make install
If you want to configure your install you should take a look at the installation notes. You can find more information about Spatial Index at the projects trac.