How do you select contacts by Business Name to add to a distribution list

You can select them from your Contacts folder, copy them and then paste them in the Members field when choosing Add Members-> From Outlook Contacts command in your DL. Upon checking the names, you can remove the header information as that of course won't resolve to a contact.

Another way to go would be to use a macro as provided in;
http://www.howto-outlook.com/howto/addcontactstodl.htm