A better way may be to use a digital camera. My Canon ZR45 works great as a go between between Vegas Video and a NTSC monitor (regular TV) with video in.

Hint: It is important to set proper NTSC paramaters, otherwise your adjustments especially for hue and blackness levels made with Vegas Video with be off since there is a siginificant difference between computer monitors and television sets assuming that is your target end playing device. If scopes and elborate monitors are out of your range you still can get good results. See seperate article entitled Setting NTSC parameters on the cheap.