It took me a while to find this fix so I'm posting my method here for successfully installing Skype in Debian
A crucial dependency of Skype, ia32-libs-gtk is broken/uninstallable in SID. This is because a dependency of ia32-libs-gtk, ia32-libs-gtk-i386 is not available to be downloaded.
Luckily The version of ia32-libs-gtk in testing DOESN'T have ia32-libs-gtk-i386 as a dependency & can be installed to meet skype's requirements.
Go to the Debian packages website for ia32-libs-gtk: http://packages.debian.org/wheezy/ia32-libs-gtk
1.Click "amd64" at the bottom of the page where it says "Architecture"
2.Select your closest download mirror & download the file
3.install it from terminal: sudo dpkg -i ia32-libs-gtk_20120102_amd64.deb
4.install skype's 64 bit debian package (http://www.skype.com/intl/en-us/get-sky ... g.debian64) via terminal : sudo dpkg -i skype-debian_220.127.116.11-1_amd64.deb
optional: apt-get any missing dependencies you still may have (I had already successfully installed ia32-libs)
I now have Skype up and running in Sid