Apple has finally opened iCloud up to everyone. Macworld tells you everything you need to know about Apple's new set of cloud-based services.

iCloud replaces the company’s oft-maligned MobileMe service, offering a central online repository for your mail; contacts; calendars; music, TV, app and book purchases; photos; documents; and backup — all for free.

Macworld Feature: iCloud - what you need to know

iCloud is comprised of several parts: seamless sync and backup for iOS devices; a server that pushes your contacts, calendar, mail, notes, and reminders to all your devices; and remote access to all your iTunes purchases. You'll need a Mac running OS X 10.7.2 and iOS 5 installed on your iOS device.

And for $25 a year, US-based customers can purchase the supplemental iTunes Match service and receive access to their entire music library (up to 25,000 songs across 10 devices), including songs not originally purchased from the iTunes store, though this won't initially be available in the UK.

Find My iPhone, previously a MobileMe subscription feature (and later opened up to anyone with an Apple ID) has been folded into iCloud, along with a component for finding your Mac. And to complete the “finding things” triptych, Apple has introduced a new iOS app called Find My Friends, which helps you coordinate with your companions via geo-location.

Users can only access locations of those people sharing locations with them; you can perennially share your location, or create a Temporary Event, which broadcasts your location to specific people for a certain time period. Privacy controls let you enable, disable, or restrict location sharing, and all of these can be further restricted within Parental Controls.

You’ll be able to sign up for an iCloud account with 5GB of storage for free starting October 12, with paid storage upgrades available - these will get you an additional 10GB for £14, 20GB for £28 and 50GB for £70 per year.

Current MobileMe subscribers will be able to transfer their account to iCloud, though they can also elect to stay on MobileMe until June 30, 2012, when the service will be discontinued. The iTunes Match subscription service will be available in the US by the end of October, with other countries to come by the end of 2011.

iCloud is available worldwide, but iTunes in the Cloud varies by country. iTunes Match and TV shows are US-only. iTunes in the Cloud and iTunes Match may be used on up to 10 devices with the same Apple ID.