Hey there,
the capture via USB is not recommended from most folks as the data rate is not big and/or consitent enough.
It would be better to either use a capture card (check BEFORE you buy one, if it is supported/certified for your OS and video app) or a FireWire card.
Should you use Premiere 5.1.c you will need to have an english language version and work on a Mac - nothing else will work.
Best is, if you have Premiere 6 already, then a FireWire card is an "easy" option.
Hope that helps.
SnowWolf