Some of my software is available as Debian packages. To install it, add the following line to /etc/apt/sources.list:
deb http://www.infodancer.org/debian /
With that line in place you can update your package index and install software by name as usual.
Be warned that packages there are not part of the standard Debian distribution and may be buggy or extremely dangerous.
The fake-qmail package is the only one I feel comfortable recommending at the moment, and then only if you know what you're doing. If you don't know what you're doing, it probably won't hurt you, but it won't be useful to you.
The rest of the packages available via that distribution mechanism may be dangerously new, dangerously old, dangerously out of date, dangerously up to date, or just plain dangerous.
I wrote a nifty little webapp to maintain the index of Debian packages dynamically, so I can update packages just by dropping a new file into the right directory. It's convenient for a small-time guy who wants to distribute his own software to his own computers and perhaps a small audience. It's not in a Debian package, but if you ask nicely, I might send you a copy.