.deb / .rpm

For Debian derivatives (such as Ubuntu)

A .deb file contains

• the files that are needed to run an application (dpkg -c pkg.deb) and
• additional data such as dependencies on other packages (dpkg -I pkg.deb).

On Ubuntu, a .deb file is apparently installed like so

dpkg -i file.deb

Red Hat, Cent OS, Fedora, Suse

RPM

Is there also a slp format by stampede?

alien (and alien-pkg-convert) is a Perl utility than can convert packages from one format to another (rpm, dpkg, stampede slp and slackware tgz).