Hi Folks,

Lenny is out for a few days now and the upgrade process is quite straight forward:
(please do that in textmode and not in your GUI, so KDE or whatever can be restarted without any issues)

• vi /etc/apt/sources.list
  (change etch to lenny)
  Should look a bit like this:
  

  deb http://ftp.nl.debian.org/debian lenny main contrib non-free
  deb http://security.debian.org lenny/updates main contrib
  

• aptitude update
• aptitude install apt dpkg aptitude
  (accept the first solution, it is fine)
• aptitude full-upgrade
  (read through the suggestion, but the first one is usually the best)
• aptitude upgrade

enjoy!