You may have noticed that “yum install apt” results in “nothing to do.” However, you can install it using YUM (centos uses YUM instead of APT). Since it requires downloading from a third party source (RPMforge). Please do so at your own risk.
Download and install the rpm forge release, which will enable YUM to access:
rpm -i rpmforge-release-0.3.6-1.el5.rf.i386.rpm
After this is installed (it takes a long time), you can install APT.
You should now be able to use apt-get and install the apt repositories. You will have to add your sources at /etc/apt/sources.list.d