The "Python bindings for the GTK+ widget set" are better known as PyGTK so that's what most people are looking for. As neither the package name nor description of python-gtk2 mentions PyGTK this package isn't found when searching for pygtk in software centre or synaptic. Adding that word to the package description would make it easier to find the right package, especially for inexperienced users.
ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: python-gtk2 2.22.0-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Wed May 4 18:50:41 2011
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
ProcEnviron:
LANGUAGE=de_DE:en
PATH=(custom, user)
LANG=de_DE.UTF-8
SHELL=/bin/zsh
SourcePackage: pygtk
UpgradeStatus: Upgraded to natty on 2011-04-30 (3 days ago)
Thank you for your bug report, the Debian is coming from Debian and should be changed there ideally