What JWG Design said. 
You may wish to add a gigundus FW drive -- DV captures will chew up disk space at the rate of a couple hundred megabytes (yes, megabytes) per minute.
Editing will indeed be painfully slow on that machine, as will transcoding the result into any other (delivery) format, so unless you have the patience of a saint, you will quickly grow impatient with the G3's limitations as a video editing machine. That said, I've used my G3 for creating VCDs from live sources from time to time. It's ok for short clips; feature-length films is a whole 'nother thing...
You may wish to add a gigundus FW drive -- DV captures will chew up disk space at the rate of a couple hundred megabytes (yes, megabytes) per minute.
Editing will indeed be painfully slow on that machine, as will transcoding the result into any other (delivery) format, so unless you have the patience of a saint, you will quickly grow impatient with the G3's limitations as a video editing machine. That said, I've used my G3 for creating VCDs from live sources from time to time. It's ok for short clips; feature-length films is a whole 'nother thing...