recommendations for password management tool

[Bill Tangren]

I'm looking for a user password management tool that will allow me to alter 
sp_max in /etc/shadow, the number of days before a change is required in the 
password. I have the set to 180, and I want to set it to 90 for all my users. 
I've googled but came up empty. Webmin (which uses usermin) doesn't do this, as 
far as I can tell.

Thanks!
Bill Tangren