The ReSharper team is actively working on next version with C# 3.0 support, but we are still fixing things for ReSharper 3.0 and even add new features!
Among with various bug-fixes, ReSharper 3.0.3 features "Global Error Analysis" feature that finds compilation errors in your solution on-the-fly. It was available in early ReSharper 3.0 EAP builds, but then we decided that it is not mature enough to put it into release. Now, we've improved it and are going to include it in ReSharper 3.0.3 update.
You can get ReSharper 3.0.3 EAP build at download page. Take a look at post about Early Access Program, if you want to learn more about participating.
To enable analysis of all errors in solution, double-click a red crossing lines symbol at the very right of the status bar and check the "Analyze errors in whole solution" checkbox. Note, that it is per-solution setting. It may take quite a while to analyze your solution for the first time (you can continue your work), but once the solution has been analyzed only those files that may be affected by the changes made are reanalyzed. Tool window with all errors in your solution can be opened using ReSharper | Windows | Errors in Solution menu command. Also, next/previous error command walks through all solution errors, if solution-wide error analysis is enabled.
We would like to hear from you about this feature! Do you like it or not? Does it work fine for you? Do you have any problems? You can leave comments to this post, or drop a message in our EAP newsgroup. Thanks in advance!