how does one go about making certain settings the same for all users on the system.

eg: I would like to have mozilla web browser automatically open pdf files with ggv- not have each user have to choose which application to use.

hey

Most configurations files are stored in /home/username/....

So for mozilla specifically, you could copy the /home/user/.mozilla directory to all the other users home directories.
This would copy a lot of things, including the history though. You could be more cunning by
setting up symlinks for only the config files you want in .mozilla to a central repository. You have to be carefull doing this sort of thing though, as any user could change the settings - unless you don't give read/write rights to the files.

I do this this for sharing my Thunderbird email box and setings between my Windows 2000 and Linux partitions on my laptop (I have to use Photoshop, so need to use Windows sometimes!). You can even share bookmarks and so on, but it takes a while to setup. Only for the really bored and those who don't get out enough.

lol@quite the contrary!!!!

The thing is I have about 100 users using linux that have only ever used windows - and to go and teach each peson how to select a specific application to open a specific file with would be tootime consuming - so i'm trying to simply set up the basics for each user. Like - pdf should open automatically with ggv etc.........

Well, if thats the case, you can do as I said. there are also ways of creating skeleton user accounts, that, so default configs are copied to the homes when they are setup. I've never done it, but it seems pretty straight forward.