Apple updated the MobileMe service today. The three areas of improvement are in Mail, Find My iPhone and a new service navigation on me.com.
Apple now offers a Find My iPhone App. You can use the app to locate your iPhone when you lose it. Of course you need to use your friend's iPhone to do that. After installing it you can sign in with your mobileMe account to locate your lost precious iPhone.
The all-new MobileMe Mail at me.com is now out of beta and available to all members.
When you go to me.com you'll see two persistent navigation features at the top of every page: a cloud icon on the left, and your name on the right.
Clicking the cloud icon (or using the key combination of Shift-Esc) opens a new application switcher which lets you move to any other MobileMe web application from the one you're currently using.
More details on the Apple MobileMe News site.
Apple really should make MobileMe free. A year of MobileMe service sells for $99. The iPhone is already expensive enough with initial cost and monthly carrier fees. If MobileMe would just come with the iPhone it would give Google a real headache. Right now I and most people I know use the free Google services on the iPhone and not Apple's MobileMe.