The free version will continue working until May 30, 2011.
That is something unheard of when starting to ask money for new versions of a product, and I wonder whether this is actually legal under the conditions the tool was provided under. Why would RedGate be allowed to take away a license for a tool downloaded previously for free?
By downloading the software I obtained a license for it. Neither point 4 nor 10 do limit the duration or schedule a termination of the license, provided that I don't breach it. As far as I understand, as long as the software remains installed on my computer, RedGate would breach its own license by making it stop working on May 30, 2011. I encourage everyone to investigate this on their own and also think about possible steps if RedGate does indeed break its own license.