I heard Nokia has some kind of business email software on the Nokia support websites to sync email but never actually tried it since honestly speaking, due to the complexity of my folder structure in Notes, I don't think it's worthwhile- besides, I'll leave that part of my work to my laptop. If I wanted work email, I would've bought a Blackberry... for now, e65 will do as a Gmail receiver along with my N93.
With regards to the topic, I currently use the Nokia PC Suite "Synchronisation" program to sync my Lotus Notes calendar, reminder and contacts with my phone. It's pretty good because any meeting/calendar invites you receive and accept are automatically transferred to the phone along with relevant alarm times. It works with both Notes 6.x and 7.x in my experience; however if it's the first time synchronising for the day on the PC (ie. First time since PC boots up) it does require the encryption password everytime to access the Notes database despite me entering it in a while ago whilst setting up. *shrugs* Small price to pay for this convenience though. I also use USB cable.