I've got an earlier version installed though the wizard. PPA install instrutions says uninstall any previous wizard version from /usr/local/ but I can't find any info on how you do this. Is it safe to just remove /usr/local/bin/kdenlive/ ?

Aren't there anybody here that knows how wizard-installed Kdenlive should be properly uninstalled?

To add more info I'm using Ubuntu 8.10, 64-bit and I think Kdenlive is 0.7.3 (info window only says 0.7).

I am sorry to say that since you installed it to /usr/local, it is not easy. If you had installed it to $HOME/kdenlive, you could have just removed that folder. Sigh - now you have a big mess!

In /usr/local, delete:

bin/kdenlive
bin/kdenlive_render
bin/melt
bin/ffmpeg
bin/ffplay
bin/ffserver
lib/mlt (folder)
lib/libmlt*
lib/libav* (first check to see if there are non-ffmpeg libs that match)
lib/libswscale*
lib/frei0r-1 (folder)
lib/pkgconfig/mlt*
lib/pkgconfig/libav*
lib/pkgconfig/frei0r.pc
include/mlt (folder)
include/mlt++ (folder)
include/libav* (folders - check to see if there are non-ffmpeg matches)
include/libswscale (folder)
include/frei0r.h
man/man1/melt*
man/man1/ffmpeg*
man/man1/ffplay*
man/man1/ffserver*
share/man/man1/kdenlive*
share/mlt (folder)
share/apps/kdenlive (folder)
share/config/kdenlive*
share/doc/frei0r* (folder)
share/doc/HTML/*/kdenlive (folders)
share/locale/*/*/kdenlive.mo
share/menu/kdenlive
share/pixmaps/kdenlive.xpm
share/applications/kde4/kdenlive.desktop
share/applications/kde/kdenlive.desktop
share/applnk/Multimedia/kdenlive.desktop
share/mime/packages/kdenlive.xml
share/config.kcfg/kdenlive.kcfg
share/config.kcfg/kdenlivesettings.kcfg

There could be more, but this is what I was able to dig up.

Thanks ddennedy!

It seems that everything was installed in /urs/local/bin/kdenlive/. Removing that and the settings-file under ~/.kde seems to have completely uninstalled Kdnlive. I can't find any of the files and folders you're listing.
Now on to installing from PPA.