If you are a MobileMe user you can turn on iDisk Sync to create a way to share files between your Macs and your iDisk storage. Your iDisk is then treated like a normal local drive and automatically syncs with the server. Other Macs using iDisk Sync with your account will automatically stay in sync as well.
Look at the services you get with MobileMe and decide whether the service is worth the price. You get email, calendars and contacts, storage, a web site, syncing, Back-To-My-Mac and Find My iPhone. There are free services that can be used to replace most of these, but they are not exactly the same.
Take a look at Back to My Mac, a feature of MobileMe that allows you to easily connect to your home Mac while away. You can share files and the screen. Back to My Mac will communicate with MobleMe so you can connect even if you are on a different network and have changing dynamic IP addresses.
If you use MobileMe, then you have an iDisk. It is a virtual hard drive on the Internet that you can use to store files and share them with others. Learn the basics of using your iDisk.
Check out the new iPhone app from Apple that allows you to access the files on your MobileMe iDisk. You can view files, share with friends and even store some locally for viewing while offline.
You don't need to use iWeb to build a Web site in your MobileMe account. All you need to do is use your iDisk and store html files in your Web/Sites folder.
You can use your own domain name with your MobileMe service. This tutorial shows you how to set it up on the MobileMe service side and the domain registrar side.
Gary Rosenzweig takes a look at what the new MobileMe service will be like, and how it will differ from the old .Mac service.
Gary Rosenzweig runs down the keynote announcements from the WWDC: A new 3G iPhone with GPS, and the MobileMe service replaces .Mac.