Left wing (PDS leaning) junge welt: http://www.jungewelt.de/ free archive
analyse und kritik: http://www.akweb.de/ monthly, archive
Sozialimsus http://www.sozialismus.de/ monthly, archive under construction
Other left-wing: Antifaschistische Nachrichten http://www.infolinks.de/an/index.htm bi-weekly, archive
konkret http://www.infolinks.de/medien/konkret/index.htm monthly, no archive
Blaetter fuer deutsche un internationale Politik http://www.blaetter.de/ monthly, archive
Liberal (SPD/Green leaning) Frankfurter Rundschau: http://www.frankfurter-rundschau.de/fr/index.htm small English section, free archive of the last two weeks, full archive $$$
Sueddeutsche Zeitung: http://www.sueddeutsche.de/ free archive of the last 30 days, archive since 1.1.98 $$$
taz: http://www.taz.de/ free archive, includes German version of Le Monde diplomatique
http://www1.zeit.de/zeit/tag/politik.html weekly, partly free archive, full archive $$$
http://www.oeko-net.de/kommune/ monthly, archive
Conservative:
Die Welt http://www.welt.de/ free archive
since you asked for the whole spectrum: Neo-Nazi: http://www.jungefreiheit.de/ weekly, archive
Search engines, link lists:
http://staff-www.uni-marburg.de/~rillingr/root1.html Last collection of links, very, very usefull
http://www.neravt.com/left/ Jays collection of links, very, very useful too, has special Balkans page
Kosvo Antikriegsseite: http://www.members.partisan.net/kosovo/index.html
www.paperball.de Searches inside German papers of the last two days
Latest headlines on Kosovo from German Yahoo: http://www.yahoo.de/schlagzeilen/politik/kosovo.html