If you have a microphone or headset attached to your PC, all editions of Vista now let you dictate as well as control most of the Windows interface through speech commands without purchasing any additional software. Choose Start, All Programs, Accessories, Ease of Access, Windows Speech Recognition. The first time you launch the program, you'll be asked to say a sample sentence and encouraged to work through the system tutorials. In addition to familiarizing you with commands that Speech Recognition understands, the tutorials help train the software to recognize your voice and pronunciation.
On the downside, the tutorials are deceptively easy, so don't expect Speech Recognition to work as flawlessly with every product as it does there. For example, although dictation and interface control worked amazingly well with Outlook 2007 and Notepad on my PC, Speech Recognition couldn't accommodate most of the controls on my Trillian instant messaging client or take dictation for chatting. In addition, the feature is very resource intensive, making it cumbersome or impossible to use on older machines. Despite these limitations, Speech Recognition can be convenient when your hands can't be on a keyboard, or when you're already wearing a headset for VoIP calls and just want to dictate a quick e-mail.