I want to allow more than one person to upload .apk files under the banner of one company to the Android Marketplace. E.g. if I work for a company called ABC I want to add two or three accounts that can upload .apk files for us. Is this possible, or do we need to pay $25 per account?
No, multiple people cannot upload to the same "account" using different usernames. This is something that Google has made comments about supporting in the future, but it is not currently supported. Using a "company" account is the only solution.