I just set up my laptop with Debian (via Knoppix - very easy, BTW) and 
got Ruby 1.8.2 loaded via apt-get (and a few more libs and packages 
that were required such as irb and libyaml-ruby - why isn't there a 
Debian Ruby package that just includes most of this stuff? - sorry 
differnt topic).

Next I downloaded and installed ruby-gems.

After this I tried using gem to install net-ssh and I got:

 # gem install net-ssh
 Attempting local installation of 'net-ssh'
 Local gem file not found: net-ssh*.gem
 Attempting remote installation of 'net-ssh'
 Successfully installed net-ssh, version 0.1.0
 Installing RDoc documentation for net-ssh-0.1.0...
 Killed

What's with the 'Killed'?  

I then tried installing session just to see if it might be a problem with 
net-ssh:

 # gem install session
 Attempting local installation of 'session'
 Local gem file not found: session*.gem
 Attempting remote installation of 'session'
 Successfully installed session, version 2.1.9
 Installing RDoc documentation for session-2.1.9...


That seemed to work OK, but when I try to require 'session', it's not 
found:

 # irb
 irb(main):001:0> require 'session'
 LoadError: No such file to load -- session
        from (irb):1:in `require'
        from (irb):1
 irb(main):002:0>



Phil