Not sure if this is a 3.1 bug or not but did a search in Maps on my 3G phone for businesss and when it was found, tapped the > to go to the info view, which had address, phone, website, etc... filled in.
Tapped Add To Contacts and selected As a New Contact. Contact screen came up, also with info filled in, tapped Done. Went to Contacts and new entry was listed with the correct businesss name at the top of the list under '#' but when I tapped the name to bring up the info, nothing but the name was in the entry.
Was able to get it to work correctly with a 3.0 3G phone.