Those applications chose not to have their drivers signed. Microsoft has
made it clear that 64-bit apps will require driver signing. They are not
blocking anyone from making drivers, and they are not forcing you to do
anything.

Microsoft owns the platform. They set the requirements for how 3rd party
programs, such as device drivers, plug in to the operating system. You are
free to use whatever program you want the correctly interfaces with the
platform. It's not Microsoft's fault that some companies refuse to make
compliant software.

It is frustrating in this beta-timeframe when there is poor application
support for 64-bit windows and driver signing. But that will change. That is
the price you pay for running the latest and greatest.

But Microsoft is doing the correct thing - even though it hurts right now.
Change is always painful.

--
- JB

Windows Vista Support Faq
http://www.jimmah.com/vista/