Script:Change password on 1000+ servers

Shell Programming and Scripting
1

Hello Folks

Scenario :

I have a linux box (expect tool installed) which connects to 1000+ other boxes (either Solaris or AIX or Linux ) with a specific id and password using SSH.
I now wish to write a script (Shell and/or expect and/or Python) which will change this existing password to a new password of my choice.

Issue:

I am not very good at this tool : expect and i am not sure how do i achieve it via shell script.

I need guidance/advice/help over how to get this done.

Regards
Abhi

2

my first google hit:
Using expect to automate password change as nested shell within bash script : expect, bash, password, script, change

there is also a complete tool for this called "passmass" which can be found here:
http://expect.nist.gov/example/passmass

maybe two good starting points!