Michael,
You don’t say in your post what release (8, 9, 10, 11) or version (Movie Studio or Pro) of Vegas you are using. I believe in either version, you can drag one clip to overlap the other clip (usually by 1/2 to 1 second) and Vegas will automatically provide a fade from the first video clip to the second. NOTE: The two clips would be on the same track.
In Vegas Pro (I don’t know about Studio) on the Transitions tab there are literally hundreds of pre-set transition effects (3D Blinds, 3D Cascade, 3D Shuffle, Dissolve, Flash, Push, Slide, Spiral, Squeeze, etc.) you can use (and then further customize to your liking). To do this, overlap your two video clips like above, then select the particular transition you want to use and left-click on the transition and drag in onto the overlapped portion of videos. This is all very simple and I believe would be covered in the users manual. Do a search for “transition” or “transition effects”.
Andrew Lenczycki