Okay, I gave the audio a good listening and figured out what was what. These TV spots appear to be for the July 21, 1978 re-release of Star Wars. There are at least 7 of them, of which 4 are included (audio and video) on the official Bonus Materials DVD. However, the others we only have the audio for (thanks again, David!). Maybe someday the video will turn up as well. In the meantime, here's some details on the 7 spots:

Star Wars 1978 TV spots

Spot 1 "Farmboy" - 30 seconds:
Luke Skywalker was just a farmboy, until he received a mysterious message.
To rescue a beautiful princess.
And defend the forces of freedom against the Death Star.
The winner of 7 Academy Awards.
The legendary Star Wars.
Rated PG. Starts Friday at a theater near you.
(on Bonus Material DVD)
(also on Hyperspace, QuickTime format)

Spot 2 - 30 seconds:
This was how it all began.
Rated PG. Now playing/Starts tomorrow at a theater near you.
(audio only - David Morgands)

Spot 3 - "What If?" 30 seconds:
What if this were all happening right now?
What if Luke Skywalker were fighting against the Death Star?
And trying to rescue a princess?
What if you could go with them?
Well... you can.
Now/Tomorrow, at a theater near you: Star Wars, rated PG.
(on Bonus Material DVD)

Spot 4 - "Adventure" 30 seconds:
No legendary adventure of the past could be as exciting as Star Wars.
The more you see it, the better it gets.
Star Wars, rated PG. Now playing/Starts tomorrow at a theater near you.
(on Bonus Material DVD)

Spot 5 - 30 seconds:
Thrilling.
Beautiful.
Dangerous.
Adventurous.
And the more you see it, the better it gets.
Star Wars, rated PG. Now playing at a theater near you.
(audio only - David Morgands)

Spot 6 - "Forbidden Love" 30 seconds:
From the moment he saw her image, he had to find her.
Luke Skywalker and Princess Leia.
In danger. In love. In Star Wars.
No legendary adventure of the past could be as exciting as this romance of the future.
Star Wars, rated PG. Now playing/Starts tomorrow at a theater near you.
(on Bonus Material DVD)

Spot 7 - 30 seconds:
Every great story has excitement and danger.
Romance and adventure.
Villains and heroes.
No matter where it happens, no matter when.
But there's never been a story like Star Wars.
And you can see it all tomorrow at a theater near you.
Star Wars, rated PG.
(audio only - David Morgands)

--SKot