Good articles and my input:
http://www.microsoft.com/exchange/techinfo/administration/2000/MailboxRecover.asp
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/exchange/exchange2000/proddocs/onlinebooks/disrec/default.asp
After installing Exchange 2000 go to Exchange System Manager and locate the Private and Public store Properties tab. Under the Database tab, check "this database can be overwritten by restore".
Dismount both Stores.
Run Veritas BackupExec, NT Backup, or any Exchange aware agent backup program and restore both Private and Public Stores from tape.
Mount both Stores and in Exchange System Manager under the Mailbox Store- Mailboxes- right click and choose run Mailbox Cleanup Agent to inform the system that the mailboxes are orphaned (all mailboxes should have Red X)
Then go to AD Users and Computers and create a new user account for the mailbox you need to access. When you get to the wizard's third screen, clear the 'Create and Exchange Mailbox' check box.
Now return to Exchange System Manager, right click the mailbox that you need to access and select Reconnect.
Apply Article http://support.microsoft.com/support/kb/articles/Q262/0/54.ASP and install Outlook to see mailbox contents on the server or run Exmerge.exe from the Exchange 2000 Resource Kit. This will allow you to export mailbox and public folder contents to personal folder file (PST) for importing into a new exchange installation.
For Public Folders I have found that you must re-mail enable them to open their contents. Since the new Active Directory does not have the attributes written for the PF's you must mail enable again to gain access.
HTH