The only way you would be able to do this is to sync you BlackBerry with one of the supported address book applications and export it from there. If you look in the address book options within the Desktop Manager it looks like the following address books are supported.
- ACT! 4.0.2/2000/6.0
- ASCII Importer/Explorer
- GroupWise 6.0.x/6.5
- Lotus Notes 5.0/6.0/6.5
- Lotus Organizer 5.0/6.0
- MS Outlook
- Netscape
- Outlook Express 4.0-6.0