i want to learn how to recive data from devices (c++) like usb cameras, but i have no clue how linux implements devices, how drivers fit into that picture, and how libs interface with them, and what libs are availabe..can anyone point me in the right direction??

i guess my first project is gonna be intercepting data from my mouse....

well as far as i know
ech device has an ascosiated /dev/devicename with it
you open it
and use read, write, and ioctl on it
but you must have a driver for it
and as far as i know most drivers are built in to the kernel
or patched and comoiled in