How to install QGIS in LMDE

The problem: Broken installation of QGIS in LMDE; Why?: There are some dependencies in a newer version, and QGIS use an older version of this dependencies. This tutorial will install QGIS 1.7.0

1) First we must uninstall QGIS and GRASS
sudo apt-get purge qgis*.* grass*.*

2) Download and install the Debian Squeeze version of the python-sip and python-qt4 for your architecture.

3) Block the installed version with the update manager. Go to Edit > Preference > Ignore packages:

4) Add the QGIS repository:
deb http://debian.gfoss.it/ squeeze main
deb-src http://debian.gfoss.it/ squeeze main

4) Update your system and install QGIS and GRASS.
sudo aptitude update && sudo aptitude install qgis grass grass-doc

Easy!