Well, depending on the program you use to edit the video, you should be able to insert transitions. Just add a text slide, and then add transitions into and out of the slide. That will affect how the text appears and dissappears on the screen.
Otherwise you could try making a small Flash file and incorporate it into the video somehow. (I've never done that, but I don't see why it wouldn't work.)
BTW, what program are you using to edit the film? What kind of camera do you have?