If you install VS 2008 Beta on a clean machine, you will find Microsoft Visual Studio Web Authoring Component in the list of installed programs. You will also find that Program Files\Microsoft Web Designer Tools\Office12 and Program Files\Common Files\microsoft shared\OFFICE12 folders with some Office 2007 components even if you don't have Office 2007 installed.
What is Microsoft Visual Studio Web Authoring Component and why does it install Office 2007 components on my machine? The answer is that it is new HTML/ASP.NET design surface that is based on former FrontPages technologies, similar to Expression Web Designer. The designer was made into a separate component, but it was hard to fully separate code from Office libraries. So in VS 2008 designer is installed using separate setup which also installs a few Office libraries the designer relies upon. This means you will get Office 2007 updates offered to you via Microsoft Update although technically you don't have Office 2007 installed. This is because Microsoft Update recognizes shared components and will offer you related updates, so don't be alarmed or surprised. Office 2007 components are fully compatible with Office 2007 so you can freely install and uninstall Office 2007 or VS 2008 and both systems will continue working correctly. Designer is also compatible with Office 2003 and should not be affecting Office 2003 applications. If you observe any disrepancies, please report bug via Microsoft Connect ASAP and we will definitely investigate the issue.
The component can be installed/uninstalled/updated separately. Setup is located on VS DVD in WCU\WebToolsCore folder. If you accidentally uninstalled the component, you can simply run WebToolsCore.exe from the abovementioned folder. The setup does not have UI, simply give it about 5-10 minutes to complete.