Follow these steps to import your Address Book from Outlook Express or Windows Address Book:

1. Find your .wab file (Example from Windows XP, C:\Documents and Settings\<username>\Application Data\Microsoft\Address Book\<username>.wab
2. Open up the "Windows Contacts" application on Vista (if you can't find it, run wab.exe)
3. From the "Windows Contacts" application, do Import, and choose "Windows Address Book File (Outlook Express Contacts)" and choose your .wab file
4. Export to .csv
5. In Postbox, open up the Address Book by doing "Tools | Address Book"
6. Do "Tools | Import" and choose Address Book and choose Text File (LDIF, .tab, .csv, .txt)
7. In the file picker, switch from LDIF to Comma Separated and find the .csv file you exported