> many administrators will wait the next release like centos 6.0/6.1.
Not the target audience, who want stable and long-term support. These people won't be in any hurry at all to upgrade from 5 to 6. Existing deployments will continue to run 5.x for years to come. If they wanted to live near the bleeding edge they'd be running Fedora, or maybe Ubuntu.
They'll download 6, when it's available, for evaluation with a view to deploying it on new projects when they're familiar with it and happy that it's no less stable than 5. Mostly, they aren't in any great hurry.
For anyone who does want a free version of RHEL 6 right now, check out Scientific Linux 6. It's not exactly the same as Centos, because SL does make a few tweaks rather than exactly tracking RHEL. However, SL 6 will be close enough to RHEL 6 or Centos 6 for most initial evaluation and prototyping, if not for deployment.