A variety of phone directories exist on-line.
Switchboard includes both white and yellow page lookups.
The GTE Superpages site includes the option to search 'nationwide' instead of just by state. AnyWho advertises itself as a directory for phone, e-mail, home pages and fax numbers. It also features a reverse look-up capability. Company Information Annual reports are one source for finding information on an individual company. Keep in mind there is no standard for reporting information, i.e. they can include whatever facts make their companies look good to their shareholders.