He said the USB connector is mainly for developers, minor inconvenience without it (more PC's with USB ports than SD). If your PC doesn't have an SD port (regular size will do, micro SD cards come with an adapter that allows them to be plugged into a regular sized slot), you'll need to use a device that allows for USB-to-external-SD-drive behavior like a digital camera for a example.
My PC is about 3 years old now and does have an easily accessible port in the front with USB/Firewire/SD/MMC/eSATA, etc. but if it didn't, I know I could use my camera: 1) Plug micro-SD card into SD adapter, 2) plug SD adapter into the camera, 3) find the USB cable that the camera came with, plug it into the camera's port and the USB to the PC obviously, 4) turn camera on, etc. You should now have an external drive that'll show up to copy all ROM files into it via explorer. That's what you'll have to do, and probably only ONCE since all NEC ROM files (plus variant dumps) total about 300 MB, so even a cheap 1GB card will do. Last time I needed a 4GB micro SD card (for my new phone), I paid $5 bucks for it retail at a pretty cool PC store called Microcenter.