I'm already building and maintaining KDE3 for Intrepid.

Right now I have opted to host the repository on my servers instead of using the PPAs so that I can work around several odd little bugs that occur during KDE3 compilation, and to maintain control over the entire build/upload process.
Madscientist, first of all thank you for your work!
Second: can you post here a little how-to install kde3 from your repos?
Sure, although you might want to wait for Troberg to test on his machine(s), just to ensure stability.
Case 1 [Already upgraded to Intrepid and are running KDE4]:1. Open a terminal window, I like to use konsole and nano
2. Type in
sudo nano /etc/apt/sources.list <Enter>
3. Paste this:
at the end of the file (you can use Shift+Insert to paste into Konsole. Now press Ctrl-X <Enter> Y <Enter> to save.
4. Type
sudo apt-get update <Enter>
5. Type
sudo apt-get install kde3 <Enter> APT will do some calculating and ask if you want to "upgrade" or not, as well as giving a list of packages that will be installed, upgraded and removed. Make sure that nothing you need is being removed, then type Y <Enter>
6. Wait for the update to complete, and then type in
sudo reboot <Enter> You need to reboot from the terminal because you have just removed all of KDE4, and therefore cannot reboot through KDM.
7. Enjoy!
Case 2 [Running KDE3 under Hardy and want to upgrade to Intrepid]:1. Open a terminal window, I like to use konsole and nano
2. Type in
sudo mv /etc/apt/sources.list /etc/apt/sources.list.backup <Enter>
3. Type in
sudo nano /etc/apt/sources.list <Enter>
4. Paste this:
into the file (you can use Shift+Insert to paste into Konsole. Now press Ctrl-X <Enter> Y <Enter> to save. Obviously if you want to use a different mirror, or select free/nonfree repositories, do that at this time.
5. Type
sudo apt-get update <Enter>
6. Type
sudo apt-get dist-upgrade <Enter> Make sure that everything APT wants to do (remove, install and upgrade) is acceptable to you, and type Y <Enter>
7. You can reboot normally--the new KDM overlays almost perfectly onto the existing Hardy KDM.
8. Enjoy!
