About one month ago Microsoft announced that in order to fulfill legal obligation in Europe with Windows 7 they will offer a Windows 7 version (namely Windows 7 E) which includes all features and functionality of the new operation system other than browsing with Internet Explorer.
IE 8 will be available as part of the "Internet Explorer 8 Feature Pack for Windows 7 E", which will be available on the Microsoft Download Center soon after Windows 7 becomes generally available.
Now of course this decision has an impact on your applications which make use of the browser. The good news is that Windows 7 E will still include the Internet Web Platform components (like for instance WebOC) which are part of the OS core. This means that the only difference between a normal Windows 7 version and the E version is the availability of the Internet Explorer 8 component. This is the same component that your users can turn off in the "Turn Windows features on and off" control panel in the Windows 7 RC build.
This also means that in order to test your applications for the Windows 7 E version, unchecking Internet Explorer 8 within the “Turn Windows features on and off” dialog should be enough.
In order to get your apps ready for any Windows 7 configuration, I therefore recommend you to have a look at the following detailed post and start to test your apps with and without the IE8 flag enabled.