There are a few tools out there allowing to check either one or the other vendor's processors or they just return the build and stepping and you have to look up the information on the vendor's website. In the past I used CPU-Z quite a lot. Many tools are of course not for free.
SecureAble by Gibson Research Corp. supports both vendors, Intel and AMD, and determines 3 important processor features and is free:
2/ Data Execution Prevention
3/ Hardware Virtualization
To the left you find a screenshot of SecureAble taken on my current desktop system.
While I haven't looked too far, I find this tools really helpful in communication with my folks here in evangelism. Almost everyone uses Virtual Server 2005 R2 and many start using the internal builds of Windows Server Virtualization ("Viridian") where 64-bit and Hardware Virtualization are key to install and run the Hypervisor. Those who are not able to buy new hardware are looking for tools to check their system and find out if they "need" a new system so they can run Virtual Server 2003 R2 with support for Hardware Virtualization or "Viridian".