When you work with multiple computers, it's easy to get inconsistent information in your calendars and address books. And it's easy to forget to copy a file from one to the other, such as from your desktop Mac to your MacBook. (Windows PCs can be part of the mix as well.) Add the iPhone or iPod Touch to the mix, and it can get impossible to keep everything synchronized and accessible.
If that's a frustration you experience, you may want to use Apple's $99-per-year MobileMe service ($149 for a family pack with one master account and four additional family members all sharing the same online storage space). Mac OS X 10.6 Snow Leopard and the iPhone OS both provide built-in support for it.
MobileMe has several components to help you keep your information automatically synchronized, as well as provide other connection advantages:
The synchronization service. The service itself keeps calendars, contacts, notes, Safari bookmarks, and e-mail up-to-date across the computers and devices you specify. It also can synchronize basic Mac settings across multiple Macs, such as dashboard widgets, Dock items, keychains (saved passwords), and system preferences; and Mail settings, such as signatures, ...