A list item in an F2 Lookup can be setup to retrieve information from your contact manager. For ACT! for Web you can retrieve company information. For a list of fields that you can use, go into the DataLink setup where you add a new field mapping and in the Contact Manager Field drop down you will see a list of all the available fields that can be used.

Example:

~ACTForWeb_Macro (tbl_contact->home_phone)