That helps immensely, thanks. So, now the bad news. iMovie is designed to work with DV Stream. Your DVD recorder does not record in this format.
You can get software that allows you to convert the video on your DVD cam to DV, but at a cost of some image quality and some tedious extra work. If you only just got the cam, I suggest you return it for a miniDV cam, which is the only platform that Mac's love to see. Failing that, please do a search through even just today's threads here and you will see the answers that you need.
iMac G5 20" 1.8 GHz - 400GB HD - 2GB RAM Mac OS X (10.4.8) 300 GB & 160GB Ext drives, QT 7.1.5 Pro, Panasonic GS-500 3CCD miniDV cam