All under the sun ( :-)

Hardware Specs (USB OTG may be not updated)
http://natisbad.org/N900/n900-commented-hardware-specs.html

Custom Kernel
The N900 comes with a 2.6.28-omap1 kernel compiled with a gcc 4.2.1
http://natisbad.org/N900/n900-custom-kernel.html

600 MHz ARM Cortex-A8 CPU

Uncovering N900 Kernels; Explored and Explained
http://www.knownokia.ca/2010/08/uncovering-n900-kernels-explored-and.html

This might be the browse able N900 Kernel Source
http://meego.gitorious.org/meego-device-adaptation/n900_kernel/trees/master/drivers/net/usb