A couple of things. Fedora.us hasn't, last time I checked, built any Extras for FC3 yet. As you can see from their download site, they are changing from stable/testing/unstable to just Extras, so you'll need to update your config to reflect that.
The stuff your looking for won't be in fedora.us, it is/will be at livna.org, though.
Thanks.
Regarding yum.conf, the new recommended way is to have a separate <packager>.repo file in /etc/yum.repo.d for each repo you use. So you might add a file fedora.us-extras.repo in /etc/yum.repo.d for that repo.
So yum doesn't care anymore about yum.conf and only uses /etc/yum.repo.d/*.repo files?
Curious, why do you have multiple urls listed like that? Is it a way to specify your own set of mirrors to rotate through?
No, I just copied it from fedorafaq.org or some other place and never changed these lines.
Christian.