Impossible d'installer Skype (erreur "Dépendances non satisfaites")

En essayant d'installer skype sur Ubuntu 12, j'ai rencontré un problème. Lorsque je tape :

sudo apt-get update
sudo apt-get install skype

Je reçois une erreur

Reading package lists... Done
Building dependency tree       
Reading state information... Done
skype is already the newest version.
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 skype : Depends: lib32stdc++6 (>= 4.1.1-21) but it is not going to be installed
         Depends: lib32asound2 (> 1.0.14) but it is not going to be installed
         Depends: ia32-libs but it is not going to be installed
         Depends: libc6-i386 (>= 2.7-1) but it is not going to be installed
         Depends: lib32gcc1 (>= 1:4.1.1-21+ia32.libs.1.19) but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

Comment puis-je le résoudre ? Est-ce que la méthode que j'utilise est la bonne pour installer skype ?

UPDATE : Si j'essaie de faire

sudo apt-get install lib32stdc++6 lib32asound2 ia32-libs libc6-i386 lib32gcc1 skype

alors j'obtiens

Reading package lists... Done
Building dependency tree       
Reading state information... Done
skype is already the newest version.
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 ia32-libs : Depends: ia32-libs-multiarch
 lib32asound2 : Depends: libasound2 (= 1.0.25-1ubuntu10)
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).