If you really mean Outlook (not Outlook Express):
Outlook stores messages in a .pst file. Windows Mail cannot import from a
..pst file unless Outlook is installed on
the Vista computer.
1. Install Outlook on your new computer
Copy the .pst file to the new computer
Open the .pst file with Outlook.
In Windows Mail, File - Import - Messages - Microsoft Outlook
For contacts:
Open Outlook.
File - Import and Export... - Export to a file - Comma Separated Values
(Windows)
Next
select "Contacts"
Next, etc.
Open Windows Mail.
File - Import - CSV (comma separated values)
locate the file saved above, etc.
Or- keep using Outlook, as it's probably better than WM