Google it: Go to Google and type in the 800 number (with hyphens). For example, if you type in the number 800-872-2657, your first result will tell you that it's the number for US Bank.
Use a 800 directory. There are many 800 number directories out there, but I've found the following directories to be the most useful:
- 800 Notes: This 800 number directory is built by users just like you who get calls from 800 numbers and then log comments about that particular number.
- Contact Help: This directory lets you search by company name or 800 number.
Now, using the search provided on these sites isn't always the best way to track down a number. Instead, use the site: search command to find a number contained within the 800 directory site, for example, site:sample.com "800-111-5555" (yes, put the 800 number in quotes).
Try a social networking search engine. Many businesses publish their 800 numbers on their social networking profiles. Social networking search engines that search across a number of different sites can track down this information for you easily. Try the following:

