debian:~# aptitude -t experimental install kde4
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
Writing extended state information... Done
Reading task descriptions... Done
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.
Writing extended state information... Done
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
Reading task descriptions... Done
my sources.list is:#
# deb cdrom:[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 DVD Binary-1 20070407-11:40]/ etch contrib main
deb cdrom:[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 DVD Binary-1 20070407-11:40]/ etch contrib main
deb
http://security.debian.org/ etch/updates main contrib
deb-src
http://security.debian.org/ etch/updates main contrib
deb
http://ftp.de.debian.org/debian etch main
deb
http://kde4.debian.net/ lenny main
deb
http://ftp.de.debian.org/debian/ testing main contrib non-free
deb-src
http://ftp.de.debian.org/debian/ testing main contrib non-free
deb
http://security.debian.org/ testing/updates main contrib non-free
deb-src
http://security.debian.org/ testing/updates main contrib non-free
deb
http://ftp.de.debian.org/debian/ sid main contrib non-free