If you have a DV or Digital 8 camcorder, go get a firewire cable and a firewire port if you need it. You should be able to get both for less than $50 total, possibly much less. You'll be amazed at how much better the results are. When you capture through USB you're probably getting an MPEG file. MPEG is a bear to try to edit. The quality stinks and it takes forever even to move the cursor around the timeline. Capturing through firewire will give you a DV AVI file which will look vastly better and be much easier and faster to edit.

If you're capturing from an analog camcorder then you might want to consider a device that converts the analog A/V into a DV stream and then capture that through firewire. Some of these are in the $200 range or less.

If you absolutely must stick with the poor USB capture, you can Ungroup the audio track from the video track (select it and press U), then slide the audio to the left about 5 seconds to line it up with the video. Once it's lined up again, select both and press G to group them back together. This should work for very short clips. If they're longer then you may find that the audio isn't just delayed, but runs at a different speed from the video. In this case you will have to stretch or shrink the audio to match. While it's still ungrouped, hold the Ctrl key down and drag the end of the audio to the left (to speed it up) or to the right (to slow it down) until it matches the video.