If you've compiled in the kernel's module autoloader support then the modules should be loaded when you first try to access the device.
If that doesn't work, you can always append these lines to your boot scripts; usually this is a file like rc.local in /etc/, /etc/rc.d/ or /etc/init.d.
Btw, the
command just tells you (the user) if the module was loaded or if it gave any error messages; you don't need to run this unless you have problems you want to debug.
Code:
/sbin/lsmod | grep usb
will tell you what modules you have loaded with usb in their names.