Free 30-day Subscription to Red Hat Enterprise Linux 4
 

With the launch of Red Hat Enterprise Linux 4, Red Hat wants to give you the opportunity to try the latest release of Red Hat's market-leading Linux technology. For a limited time, you can download a free 30-day subscription to the Red Hat Enterprise Linux 4 product of your choice (AS, ES, WS, or Desktop).

http://www.redhat.com/software/rhel/eval

i think it will coust me more as 30 day's to understand redhat :)

I've up2dated my RHEL 3 update 2 box to the latest via rhn, it just like we used Red Hat Linux's up2date demo service before. Would Red Hat allow users to reactivate their demo accounts for free in the future? :P