There are new debs available at:
(dated 26 Mar 2012)
Being on Slackware64 I used spotify-client_0.8.2.639.g79d339d.504-1_amd64.deb.
First we create a Slackware package from this and install it.
mkdir -p work/pkg
ar -x /path/to/spotify-client_0.8.2.639.g79d339d.504-1_amd64.deb
tar xvf ../data.tar.gz
Then, as root, you run makepkg in the work/pkg directory:
makepkg -l y -c n /tmp/spotify-client_0.8.2.txz
then cd /tmp as root and
Next we need a few symbolic links, for these you need to make sure you have the seamonkey-solibs package installed. (I had 2.8 already from doing a full install. If you haven't got it, it's in the 'l' directory):
ln -s /usr/lib64/seamonkey-2.8/libnss3.so /usr/lib64/libnss3.so.1d
ln -s /usr/lib64/seamonkey-2.8/libnssutil3.so /usr/lib64/libnssutil3.so.1d
ln -s /usr/lib64/seamonkey-2.8/libsmime3.so /usr/lib64/libsmime3.so.1d
ln -s /usr/lib64/seamonkey-2.8/libplc4.so /usr/lib64/libplc4.so.0d
ln -s /usr/lib64/seamonkey-2.8/libnspr4.so /usr/lib64/libnspr4.so.0d
(I assume, as I haven't tried, that if you are not on Slackware64 then you can simply replace 'lib64' with a plain 'lib' in the above).
We now need GCONf which is available at Slackbuilds.org (and ORBit2 as a dependency, also available on Slackbuilds):
and that should be it.
in a terminal and you're good to go.