I discovered that, after one installs Office 2007, one can add components that were found in Office 2003, which includes the speech recognition components. Simply after installing Office 2007, put the Office 2003 CD into the drive and start the installation procedure. Choose to do a custom install and then disable the installation of everything except the Office Components (which should run all from disk). Then complete the installation. Voila...speech recognition is back.
Hope this helps!