At heart, there are two types of PlayStation Network account - a master account, and an associated account. The chances are that most gamers will use master accounts, but associated accounts will be especially useful for families - where, for example, a parent (who holds a master account) wants to be able to limit the amount that their kids (with associated accounts) can spend in the PlayStation Store.

Either way, you create an account through a fairly simple process - a set of screens which ask you for sign-up information, and you're done. Those screens are actually displayed using the web browser component of the operating system, so it's just like filling in a registration form on a remote website - and then you're done. Every user on PlayStation Network has a single unique ID and sign-in details, just as you'd expect on any online service - and those sign-in IDs are global, so you'll be able to add your friends to your list regardless of where in the world they are.

Oh - and it's all free, too. The only place you'll be asked to fork over a penny is when you purchase something in the PlayStation Store - all of the online services, from sign-up right through to voice and video chat, are free, as is normal multiplayer gaming. There's no equivalent of the Xbox Live Gold account, where you're expected to pay extra for a further tier of services - the only things you'll pay money for are paid-for downloadable content, or subscriptions to premium services like massively multiplayer games.

So, once you add friends, what can you do with them? Obviously enough, you can check their status and see if they're online; you can see if you have any new messages from them, and send them messages. Sending emails through the system uses the same peculiar text messaging style keypad that users of the PSP will be familiar with, which seems a bit painful at first but rapidly becomes a much faster way of entering text than the on-screen keyboards used by other systems - however, if you're not really keen on using that to enter an entire message, you can always plug in any standard USB keyboard, which will work with any text entry field anywhere on the system, as well as with the web browser. As to the content that will be available, Sony is still playing its cards close to its chest to some extent - but one thing the giant firm is clear on is that the PlayStation Store will grow to encompass more than just new game content and demos. Alongside the free and paid-for game content, the store will also play host to a wide range of new titles developed specifically for download (the first of which, fl0w, was shown off at TGS - dozens more PlayStation Store exclusive titles are being worked on around the world thanks to an initiative which Sony launched at GDC last year) - and as Ken Kutaragi revealed at TGS last month, it'll also be possible to buy PSone and PS2 classics you missed out on, as well as a selection of PSP games, from the PlayStation Store, and download them directly to your PS3.