NOKIA WORLD MAY prise some eyeballs away from Apple's September announcements when people start talking about the way Linux-base Maemo software delivers a PC-like experience on a handset-sized device. Nokia's N900 (I call it a Nokbook.) is more than a generation beyond Nokia's earlier internet tablets. With the new Maemo softare, the N900 can run with dozens of open application windows while taking full advantage of cellular telephony features. The Nokbook lets people multitask and browse just like on their desktops. Maemo is an open source operating system that could capture consumer mindset because of its openess. Its kernel can easily connect mobile handsets to systems in digital homes.