http://www.limewire.com/english/content/download.shtml
is the ONLY place to get the official LW! Yes 128 MB ram even just for running osx is really cutting it fine to say the least. No wonder your apps slow to a crawl. I hate ram issues & learnt the hard way in the early days. It will affect noth the speed of your os & any apps that struggle to obtain any real ram. My hint of the max for your iMac was just making the point of what you 'can' have. I use 1.5 GB personally for a G4. But as et voilà pointed out, the max is overkill for your machine nowadays. You obviously don't use it for high-end graphics or such anyway. So is that a SCSI external/usb/firewire hdd?