On my desktop machine, Debian Woody with 2 usb ports on the motherboard, and a card with 2 more usb ports running a 2.4.26 kernel, I had to add the kernel modules needed into /etc/modules, so that they were loaded at boot time.
My /etc/modules looks like this:
Your system (FC3) may have a different place to list modules to be loaded at boot time, I'm not sure, as I've never used FC3.
I do know, however, that the kernel has to know how to talk with a particular device, including usp ports, and as such needs either the drivers compiled into a monolithic kernel (not the usual way), or compiled as a module, to be loaded as needed. Kernel modules are quite speciffic to hardware. For instance, a 3com 3c509 driver will work well for that board, but won't work at all for a NE2000, even though both are ethernet adaptors.
You may have to determine what usb ports (chip set / board manufacturer and modle) you actually have, then look in /lib/modules/your-kernel-version/kernel/drivers/usb (or similar) for the driver for your usb ports, then add the drivers to /etc/modules or whatever. you can test by doing an insmod for the module you have. If you do not have an already compiled module in /lib/modules for your ports, you may end up compileing a kernel with the required drivers.
As always, read the man pages for insmod and modprobe, and be sure to read the README in the top level of your kernel sources. also there is doccumentation in /usr/src/your-linux-sources/Doccumentation that might help you further
Hope this helps,