Sony has announced PlayStation Plus, a new online service forPlayStation 3 owners. While the features of the free PlayStation Network service will remain unchanged, Plus adds game downloads, auto-patching and other exclusives.

The premium service will launch on June 29 and cost $49.99 for one year or $17.99 for three months.

Cross-game voice chat has been requested by gamers in the past, and it’s something that Microsoft’s Xbox Live Gold service (which also costs $50 per year) already offers. Now you’ll be able to do it on the PS3 too, according to Joystiq.

When playing with a friend over the Internet, you’ll be able to switch between games without interrupting your voice chat conversation. Cross-game chats must be initiated by a Plus member, but they will include non-Plus members so long as the premium subscriber is present.

In addition to getting exclusive or early access to beta testing periods or playable demos, Plus members will be able to play some full games for up to an hour before choosing whether or not to buy them. Finally, they’ll get access to the already-launched Qore premium video series, which offers glimpses at new games and gamer culture.

Many of the new features are already available to Xbox Live subscribers, but if you want to play the Xbox 360online, you have to get a Gold subscription. The PS3 already offers basic online play without charging its users. Since the benefits are just icing, not essentials, will you spend $50 per year for a Plus subscription?