This is by far the most comprehensive page I have seen for those developing software or hardware that will be compatible with Windows 7.
I copied some parts below that should convince you to check the site out…
Opt-In to Receive Updates
Review the Documentation
Download the Toolkit
Test and Submit for the Logo
Get listed in the Windows 7 Compatibility Center and reach millions
Today, millions of customers and sales professionals use the Windows Vista Compatibility Center to discover compatible devices and applications. Soon, we will be launching the Windows 7 Compatibility Center.
Be sure your products get listed in the Windows 7 Compatibility Center by submitting your compatibility status directly to the Compatibility Center Team