Jetbrains are making the next version of ReSharper available via an Early Adopter Program. This allows you to get ReSharper for free util the EAP program finishes. This is even if you have evaluated ReSharper before.
Details are at http://confluence.jetbrains.net/display/ReSharper/ReSharper+Early+Access+Program
Downloads at: http://confluence.jetbrains.net/display/ReSharper/ReSharper+6.0+Nightly+Builds
Before downloading one of the nightly builds you should check that is has been sucessfully installed and used by others. You will need to put in a new version roughly every 14 days.