Monday, June 21 is coming up in a few days, and with it Apple will bring the iOS 4 update for existing iPhone 3G/3GS and iPod touch (second & third generation only) devices. That means that iOS 4 compatible updates are starting to appear in the App Store, and among them is Dropbox, now at 1.2.2.

If you’re already a fan of Dropbox, the easiest way to sync and share your files online and across computers or iDevices, the new about iOS 4 compatibility will be no doubt most welcome. Whether you’re updating your existing iPhone 3G or 3GS or iPod touch (second or third generation) to iOS 4 on Monday when Apple makes it available or holding off for your swanky new iPhone 4 to arrive in one week, Dropbox is ready for you.

Apple only started accepting iOS 4 apps less than a week ago, and the new Dropbox 1.2.2 update is likely to be only the first of a tidal wave of App Store updates coming over this weekend in anticipation of the release of the new iOS 4.

As MacRumors notes, iOS 4 is bringing with it Apple’s form of multitasking to a few key areas, with seven specific background services:

Background audio: Allows your app to play audio continuously.
Voice over IP: Users can now receive VoIP calls and have conversations while using another app.
Background location: Navigation apps can now continue to guide users who are using other apps
Push notifications: Receive alerts from your remote servers even when your app isn't running.
Local notifications: Your app can now alert users of scheduled events and alarms in the background, no servers required.
Task finishing: If your app is in mid-task when your customer leaves it, the app can now keep running to finish the task.
Fast app switching: This will allow users to leave your app and come right back to where they were when they left -- no more having to reload the app.

The first wave of iOS 4 compatibility updates will likely be mostly centered on the new fast app switching, which allows you to switch in and out of an application without restarting it. It’s too early to tell when more impressive multitasking apps such as Pandora or Skype will get an iOS 4 compatible update, but our fingers are crossed that it will come sooner than later.

In the meantime, Dropbox 1.2.2 is available now for your downloading pleasure from the App Store. The universal 4.6MB app is compatible with all iDevices running iPhone OS 3.1 or later.

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