planet is a famous python software to combine the feeds of various blogs (or other feed-sources) to one website. It's used by various free software projects, organizations etc.

While thinking about creating a planet karlsruhe, I thought about possible licensing/copyright problems, in theory you would have to ask everyone you aggregate. As there are many blogs using free or semi-free licenses like FDL or Creative Commons that at least allow re-distributing unchanged content if you stick with the license, adding license-data would make it perfectly legal to add those feeds without asking.

planet is already flexible enough to do this, as you can just add additional variables. Change the config.ini to something like this:

[http://www.hboeck.de/feeds/atom.xml]
name = Hanno Böck
license_name = Creative Commons by-sa
license_link = http://creativecommons.org/licenses/by-sa/2.5/

Add some Code to the template:

<TMPL_IF channel_license_name>
<TMPL_IF channel_license_link><a href="<TMPL_VAR channel_license_link ESCAPE="HTML">"></TMPL_IF>
<TMPL_VAR channel_license_name ESCAPE="HTML">
<TMPL_IF channel_license_link></a></TMPL_IF>
</TMPL_IF>

And you're done.