of the wireless bridge.
You connect your iMac to these devices with a short length of ethernet cable and your iMac becomes wireless.
However, if you are looking for a USB Wifi device because your onboard ethernet has failed, then you are right, these will not help.
As for what iLife version you would need, about the only version that "may" run on that machine is iLife 03 and even that requires OS X 10.1.5
You did not give much information about your machine, other than it was a tray loader (which puts it in the early editions) so we do not know your processor speed, possibly 333Mhz, but what is really holding you back is that old OS. While 10.1 was better than 10.0, neither of them were very good or stable.
All that being said, you should be able to run OS X 10.3 on that machine if you were to max out the memory.
P