I work at IBM, in Lotus Domino after sales tech support.
This info, about supported phones, is public on ibm.com:
Nokia devices compatible with IBM Lotus Notes Traveler:
Nokia E71, Nokia E66, Nokia E90 Communicator, Nokia E70, Nokia E65, Nokia E63, Nokia E62, Nokia E61i, Nokia E61, Nokia E60, Nokia E51, Nokia E50, Nokia N96, Nokia N85, Nokia N79, Nokia N95 8GB, Nokia N95, Nokia N82, Nokia N81 8GB, Nokia N81, Nokia N78, Nokia N77, Nokia N76, Nokia N75, Nokia N73, Nokia N93, Nokia N93i, Nokia N80, Nokia N91, Nokia N92, Nokia N71, Nokia 3250, Nokia 5500, Nokia 6290, Nokia 6110 Navigator, Nokia 6120 Classic, Nokia 6121 Classic, Nokia 6122 Classic, Nokia 6124, Nokia 6650 Fold, Nokia 5320 XpressMusic, Nokia 5700, Nokia 6210 Navigator, Nokia 6220 Classic
This feature is provided by a new client app that runs on your phone, called IBM Lotus Traveler.
http://www-01.ibm.com/software/lotus/products/notes/traveler.html
A version of this app, for Windows Mobile 5 and Windows Mobile 6 devices, has been shipping with Lotus Domino since R8.0.1 came out around March this year. Traveler for S60 will ship with Domino R8.5, and will offer the same features as Traveler for WinMo does today. So go to that link and review what the WinMo version does, this will give you a good idea of what to expect.
I wouldn't exactly call it a 'port' of the WinMo app, the guts of it (network protocol handling etc) is ported from the WinMo app, but the UI has been rewritten, so it conforms to the S60 UI guidelines. One thing you may notice is that part of Traveler is an email client, so it wont sync emails to the S60 Messaging app. But Calendar, Contact, Notes and Tasks data from the Domino server WILL sync into the S60 equivalent apps.
Andy