The above graphic is what greets you when you visit .Mac. Apple is not hiding the fact that MobileMe is the successor to .Mac (which itself was the replacement for iTools, which some might recall was free). Now, many .Mac users might be worried about how the transition from .Mac to MobileMe will take place and what will happen to their .Mac email addresses, .Mac website addresses, and all the information that they have in their .Mac mail accounts, contacts, and so on. Apple has posted a handy little Knowledge Base article which details what .Mac members should expect.
The short version is that your .Mac account email address will work just as it did before, but you'll have a choice of using either firstname.lastname@example.org or email@example.com. If you have aliases setup at .Mac they will continue to work as well. All your .Mac websites will continue to work at both mac.com and me.com. Your email and contacts will magically be transferred to MobileMe, but you will no longer be able to check you accounts using Mac.com's website: it'll all happen over at Me.com.
Also, the increased storage limits will be applied to your account, but it might take up to 10 days after the migration from .Mac to MobileMe before you see the new limits reflected in your accounts.