Gamespy has a very interesting article regarding the future of Sierra/Monolith's stealth FPS, No One Lives Forever 2. According to the article there are plans at Monolith for future releases of both a tool package and an expansion pack for NOLF2. An add-on is expected later this year, as well as a new (mainly multiplayer patch (in the next 2 weeks), and tools for the mod community. The new patch will have 10 new maps (mostly adapted single player maps), a new multiplayer mode "Doomsda".
Gamespy also hints to a possible NOLF3, which we here at WP have been suspicious about for a while, especially since the NOLF3.com is already registered to Fox Interactive.