Microsoft has released a cool user agent utility for IE 7, User Agent String Utility. This lets you report your browser version as 6.0 to sites that require that.
From the utility's description:
Whenever Internet Explorer releases a new major version, Microsoft makes every attempt to coordinate the change with major web site owners so that users who upgrade to the latest version can take advantage of new features available on the upgraded browsing platform. A character string called the “User Agent String” identifies the major version of the browser to web sites so that the sites can offer certain functionality on particular browser versions. In some cases, websites might misidentify a new version of IE as an outdated version, with results ranging from rendering and behavior issues to total rejection of the user. This utility changes certain registry keys on an IE 7.0 installation to allow a user to emulate an IE 6.0 installation as a simple workaround until problematic sites update their code. It also offers users the option to report these problematic sites to Microsoft.
The coolest feature of this tool is that it allows you to report sites that are still incompatible with IE 7 so that their owners can fix their compatibility before IE goes final.