JetBrains has a preview release of ReSharper for Visual Studio 2010 available now for download.
From the site:
"ReSharper for Visual Studio 2010 (preview) - is an early build for those who are trying out Visual Studio 2010 and cannot live without ReSharper. It is neither 4.5.1 for VS10, nor 5.0 for VS10. It is intermediate result of our attempts to integrate with Visual Studio 2010 extensibility model, plus preliminary state of some of ReSharper v5 features (you will find some of them enabled). Complete roadmap for ReSharper v5 will be published soon."
Hey - it might be a preview but it is better than nothing!
http://www.jetbrains.net/confluence/display/ReSharper/ReSharper+for+Visual+Studio+2010+(Preview)