Based on Lotus Notes 6.5 it looks rather easy. You can export the address book as a vcard (v2.1 or v3.0). A quick test shows that it imports into Address Book just fine.
I've never used the journal so I don't know how well it exports, but it does have some text options, along with Lotus 1-2-3 (which can be imported into Excel and then saved into antother format from there).