You can use Alien to do this; Alien is a neat little tool that converts back and forth between RPM and Debian packages (plus SLPs and .tgz packages). First, see if you can install it via yum:
If that doesn't work, type this in the terminal emulator of your choice to install it manually:
su -c "yum install alien"
Those steps are derived from this page. Assuming that's all successful, you can then install any .deb package via the following:
cd /home/(your username)/Downloads/(whatever directory you want)
su -c 'rpm -i deb-1.10.27-3.i586.rpm'
su -c 'rpm -i html2text-1.3.2a-3.i586.rpm'
su -c 'make PREFIX=/usr install'
Hope that helps! Let me know if anything doesn't work or if you have further questions.
alien --to-rpm <name of package>.deb
rpm -i <name of package>.rpm