As mentioned,
CGTalk.com is very good. Also, for free text and video tutorials I recommend
www.3dbuzz.com. Also as mentioned,
www.maxon.net has many good tutorials and the actual manual for version 8.5 (not sure if they've actually updated the manual since 8.2) is very well put together. If you download the 8.5 demo, make sure to download the tutorials and project files as well.
Good luck with your 3d endeavors. I have found Cinema 4d to be the most stable and easy to use compared to Maya 5.0 and Lightwave 7.5. As a company, Maxon has consistently supported the Mac community much better than Alias or Newtek. Out of these three 3d apps, Cinema 4d performs just as well, if not better, on the Mac as on the PC. I don't think the same could be said for Maya and Lightwave, although I haven't tried Maya 6 or Lightwave 8 so please correct me if I'm wrong.