In HAM click the top menu and then select application catalogues.
This will then list your repos.
devel and testing repos are for unstable apps and download from here should be done with caution.
If you which to install a devel or testing application

@hella
I have no problem with customizing etc, that's the maemo spirit, it's why we are still here.
But pointing a newbie at overclocking and not explaining the facts is poor.
It's his choice to make not everybody else's.

@OP
Everything you need to know about maemo is in the wiki's
wiki.maemo.org have a search on there.