okay, you'll need to install something called usbmgr (its what i use for my usb mouse) and usbview (handy app to view usb devices) in your kernel you will have to add the kernel module to support USB and USB printer/scanner devices. so if you know the RH equivilent to debians
'modconf' then you should be set. (i think you need to find the rpm modutils)
or you can try insmod (module name) when you know what the module is called.
im not sure but if anybody else can fill me in what is the directory where linux keeps the modules? /usr/lib/linux/ or something...?
edit: pick out your right distro from here for the modutils package, install then run 'modconf' and you should go thru the directories and find the right module to install for USB scanner. make sure you know your chipset on your motherboard.
http://rpmfind.net/linux/rpm2html/search.php?query=modutils
theres also a little application called 'gmodconfig' which you can use, however im not sure the reliability (bugginess) of the application.