Howto fedup?

[Neal Becker]

How do I use fedup to update f17->f18 (via net)?

I tried:
sudo fedup --network 18
setting up repos...
default-installrepo/metalink                             |  26 kB     00:00     
Could not parse metalink https://mirrors.fedoraproject.org/metalink?repo=fedora-
install-18&arch=x86_64 error was 
No repomd file
Error: can't get boot images.
The installation repo isn't available.
You need to specify one with --instrepo.