The deltaiso for the RC3 -> RC4 i386 DVD image is available now (2.9% of
full ISO size, applydeltaiso time ~ 3 minutes). The x86_64 bit version
will be available in a few hours. (I don't normally announce them
anymore, but still make them available, and the install test results
page has the link.)
https://fedoraproject.org/wiki/Test_Results:Fedora_13_Alpha_RC4_Install
http://thepiratebay.org/user/andre14965/