Entourage can import a .csv file. Just select the option in Outlook to
export as .csv or text file. In Entourage select the Import --> Contacts
from a text file --> tab delimited file and navigate to the .csv file.
Other options that have been found useful by users:
Transfer Windows® Outlook® email, contacts, and calendar appointments from
your PC to your Macintosh® computer! See this MacTech article for more info
on using Outlook2Mac.