there's a simpler way:
Step 1: Draw a white line with the brush (Hold shift to keep it straight), or a very light colored version of the sabers color.
Step 2: Convert to symbol
Step 3: go to filters-glow-red set to 20-25
Step 4: Set strength 250-280
Your done
Umm....judging by the posts this was last 2005...but i just wanna know something...how can you make the trail of the lightsaber? please someone answer..... :(