@Tinkster: Thanks for that. But I have a laptop, and I don't have a connection in my room in Uni. I have to use the library. So when I boot up in the library, there's DHCP, whereas at home, no DHCP. I don't really want to configure /etc/sysconfig/networking/devices/ifXXXXXX all the time... I'd rather have DHCP on all the time.
@secesh: I am using FC2 and i dont have the dhcpd script. I do however have the network script which seems to be something to do with dhcpd instead. However, after some digging, I came to a script in sbin which is /sbin/ifup... I can't really read bash scripts, and there was nothing to do with -t option in there...
On second thought, is there a command that can change the interface from being static to dhcp?