The new premium service, called PlayStation Plus, launches later this month, and will give subscribers access to an "exclusive set of content and features designed for gamers," including access to early game demos and priority betas, automatic downloads for background updates, and free content that will include full PlayStation Network games, themes, and even discounts in the PlayStation Store. Access to Qore is also included in the 'Plus' package.
Those who are satisfied with their current (free) PSN service will be able to continue using it. Subscribing to PlayStation Plus will cost $49.99 per year, or $17.99 for a three month plan. Sony has also announced that they'll be offering three-month free trials for a limited time.
No mention of PS2 games on the PSN yet?