applesyncnotifier.exe is a AppleSyncNotifier belonging to MobileMe from Apple Inc. Now that the iPhone 2.0 is available iTunes is adding a new “MobileMe” file called Apple Sync Notifier. This file installs with iTunes and is used when syncing your iPhone, iTouch, iPod, etc.
It is required for the proper functioning of Apple products so it should not be removed.
Non-system processes like applesyncnotifier.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues