Online Trick

Quick Tip for Austrian QGIS Users: How to Use Bergfex (OEK 50) Topographic Map as Base Map in QGIS

In the below stackexchange postings you will learn how to get a custom tile source running on QGIS using the OpenLayers Plugin.

http://gis.stackexchange.com/questions/69907/easiest-way-to-create-historical-street-maps-using-qgis
http://gis.stackexchange.com/questions/56615/how-to-add-another-layer-origin-in-my-installed-openlayers-plugin
http://gis.stackexchange.com/questions/70648/using-custom-source-for-qgis-openlayers-plugin

For the Bergfex tile source you can find the working html-file here:
https://gist.github.com/gimoya/6450983