Can beige G3 machines support USB?

Sure can. Just buy a PCI USB card and slap it in. You should be good to go.

you just need to watch what chipset that the USB PCI card uses, cause some can be very problematic at best or just not work. cause the chipset might draw to much power from the pci bus and the OS will disable the card from working. or you will run into crashes.

you also need to make sure the chipset is OHCI (or is it OHIC) compliant cause if its not you will run into problems. mainly in Mac OS 9.x . now OS X might be able to use those non OHCI (or is it OHIC) compliant cards but i would not take the chance.

i seen one USB2.0/Firewire PCI combo card that has a PSU connector on it so it wont use the PCI bus power but the card isnt OHCI (or is it OHIC) compliant. they sell these at radio shack for $19 USD. my friend bought one and in OS 9.2.2 the usb side wont work but firewire works great. in OS X both sides work great. i am not for sure if he connected the power up to the card that might have been apart of the problem. but i know that the extension drivers for USB cards in OS 9.2.2 will only work with OHIC ( or is it OHCI) compliant cards.

Cards with the OTPI chipset, especially those sold under the Belkin name, have been notorious for problems on a Beige G3
but on the same note some OTPI chipset on a Keyspan card has been known not to have problems. also on the same note the problems have only been seen on the USB only cards. the combo usb/firewire cards with the OTPI USB chipset havent had problems

cards with a NEC chipset are hit and miss but more than likely work.

but as soon as you add a video card to the mix the system will get very unstable. some times can be fixed if you move the cards around. most people that have cured the system after this have moved the USB card into the cranter PCI slot and the video card into the 1st PCI slot ( next to the Personality card).

my USB 1.1 pci card has a Lucent chipset in it and i have had no problems with it , i also have a Radeon 7000 and a Belkin wifi G+ PCI card installed and the usb card is still working fine. it could also be that i have it in the center PCI slot. these also can be hit and miss cause some Mac's didnt like the chipset

just do some research with google useing the terms Beige G3 and USB PCI or USB/FIREWIRE combo cards, something will turn up. but look to buy a USB2.0/Firewire combo card to buy , sometimes you can find them at a good price

Thanks. I would also like to know if there was a way I can install OS 10.4 on the machine.

do a google search for Beige G3 and OS X tiger install

which will lead you to info about xpostfacto ( a helper that will allow you to install unsupported OS X versions on most machines)

it will be found here
http://eshop.macsales.com/OSXCenter/XPostFacto/

but be warned tiger sometimes has issues installing on a Beige G3. not every Beige G3 machine will accept a tiger install. there are very few people running tiger on one cause of that. i am one of the few that has tiger installed and running 99.9% stable

most people shoot to install panther cause most Beige G3 systems will accept that version of OS X more so than tiger.

also any version of OS X from 10.2.8 - current have issues with the onboard video going out at random. if you are not useing the onboard video then you do not need to worry, i had to cause i use a Beige G3 AIO.

and i had to do the 2 terminal commands shown here
http://docs.info.apple.com/article.html?artnum=25564

but i had to take a few extra steps. i had to have a PCI video card to do this cause after you do this and reboot ( after you install 10.4 and repair permissions) the onboard video is disabled and the PCI video card is the only thing that is working. use software update and update to the latest version of OS X and reboot. then the onboard video will be enabled never to have a blackout again.
but thai is IF you still use the onboard video.