Use Sarge unstable cds for Etch?
 

I got a Debian Sarge unstable net install cd lying around. Since Sarge's packages rarely get updated I'd like to go with Etch if it's stable enough. Can I use the Sarge network install cds for this?

This should be possible.

You will want to boot the installer in "expert" mode. (type "expert" or "expert26" at the boot prompt.) The installer will ask a lot of questions and possibly give some errors. You will want to install the "testing" branch from a mirror rather than the CD. (This is why you use expert mode.) You should probably do a test installation just to see what you are up against and so you can post any questions or problems/errors.

It's no need to use expert mode to install from a certain repository as far as I know. Simply answer the few questions at the beginning, then, when you're asked for the install method, select FTP and you also have an option on editing the sources.list file yourelf, so you can point it to /testing.