In my system, while starting up, a process called udev is started after kernel says Welcome to Fedora Core 6. Is udev really required? If not, can i uninstall it so that my startup time will reduce a bit?
yes udev is required in the new kernels.
Read the wikipedia page for more info on it *en.wikipedia.org/wiki/Udev
without udev,u wont have device files made for u;network nodes,h/w devices etc.
btwn system-config-services will be able to help u stop starting those NFS services etc.