Hi There,
I was wondering if there is any way in Linux in general and Fedora 13 in particular to configure system so that any service that needs access to internet will have to ask for password/permission to do so. So that I can

This is for a Desktop not server.

Thank You

that question seems kind of generic, you could however turn a generic garage sale machine into an authentication server that requires you to put in a name and password at the beginning of the session to authenticate any access outside your network
i've never done this before so i can't provide much specifics on how to do it but it's just an idea
perhaps this will work:
http://www.linux.org/docs/ldp/howto/...reeradius.html

Thank You for your response..
I am a newbie and am not much skilled in linux......can you please give me some other method like configuring some files etc...

even configuring an authentication server really comes down to editing files when you get down to it, other then some sort of software designed for said function there really isn't much you can do
a quick and dirty method perhaps would be to edit /etc/network/interfaces so the interfaces do not come up by default then make sure that only root has permission to bring the network online period but that would reacquire constant intervention so it would not be practical for your purposes,

another quick and dirty way would be to configure a firewall to block all outgoing traffic but again that would require either your intervention or giving someone else privileges to temporarily disable the firewall

as you can see, the easy solution is often the worst solution, i wish you luck, perhaps this would be a good opportunity for you to learn a new trick