Apple has posted new articles on how to replace a battery in the unibody MacBook and MacBook Pro’s. You can access the hard drive inside this area also. You can check it out right here:
The 17″ MacBook Pro is not quite so easy. You have to take off the whole bottom case, not a big deal, but it might scare a few people away. Here is the link from apple for the 17″,
And, here is another link from a third party for a more detailed procedure on getting into the new MacBook Pro 17″.
Upgrading the RAM on the 15″ unibody MacBook Pros is much more difficult than older models. Here is a great video on how to do it:
This is a long web address, but the video is very helpful. Upgrading the RAM chips on the new MacBook Pro Unibody might be a little intimidating to some folks, but it is definitely doable.