Incognito is dead! Long live T(A)ILS!
 

Well, at least the old Gentoo-based Incognito is no longer maintained or developed. Incognito has merged with a similar Debian-based live distro project called amnesia, resulting in The (Amnesic) Incognito Live System, or simply T(A)ILS. Go check it out! The old Incognito is dangerously out-dated any way.

Note that any questions about T(A)ILS should be done at the T(A)ILS forum, not here.

Why I get the warning from firefox "The connection is untrusted "
What is so special about the the website ?

It's because neither your operating system nor your web browser include CAcert's certificate, which is used for authenticating the T(A)ILS website and encrypting your connection to it. It should be pretty safe to just ignore the warning and choose to proceed anyway, but installing the certificate is a better idea and will prevent you from getting the warning in the future.

The CAcert certificate can be downloaded here. Here's a quick breakdown of what to do depending on your web browser:

• If you have Microsoft Internet Explorer 5 or 6, just click on "Click here if you want to import the root certificate into Microsoft Internet Explorer 5.x/6.x".
  
• If you have Mozilla Firefox, just click on either Root Certificate (PEM Format) or Root Certificate (DER Format), check the box which says "Trust this CA to identify websites" and click OK.
  
• If you have Opera, just click on either Root Certificate (PEM Format) or Root Certificate (DER Format), then choose "Install".
  
• If you have Google Chrome (or Chromium), download either Root Certificate (PEM Format) or Root Certificate (DER Format) and go into Chrome's options -> Under the hood -> Manage Certificates. There you select to import the file you just downloaded, and remember to choose to "Automatically select the certificate store based in the type of certificate".

For other browsers I do not know exactly what to do, but I'm pretty sure the procedure is close to any of the above instructions.

why is TAILS not listed as free software????

Seems the forum is dead too.