Can someone give me an example of a major scale in a known song? 
I'm kind of confused now...
Take a listen to Wild World by Cat Stevens. It is in the key of Aminor, which is the relative minor of C Major (all white keys on piano), and uses the same notes. The reason I chose this song is b/c the little flourish (riff) at :57 and throughout the song is simply the descending C Major scale. Start on the Middle C key, and hit every other descending white key until you get to the next C key. Pretty simple, and it's a great example of a major scale used in a song.
I think the biggest reason for Western music utilizing the Major scale as much as it does is harmony, how the different notes relate to the tonic (the I of the scale), and the tension and resolution created by using particular combination of notes of this scale together.
An understanding of music theory is not as daunting a task as it may seem, depending on how deep you want to get. Music contains only 12 notes; 7 "notes" plus 5 sharp & flats. The notes came before any scale. Over time people played various patterns of notes together, if these combination of notes worked for their purpose, they would call it a "insert name"scale. Some scales are easy to construct, like the whole tone scale; others are a bit more involved, like the Melodic Minor which will raise the 6 & 7 degreess a half step when ascending the scale, then lower them both back a half step when descending.
There are thousands of scales out there, but you'd be best off getting a grip on the major, then going from there. Knowing the Major scale well will give you the knowledge to construct the modes, minors, pentatonics, pretty much any scale you'll use in Western music. it's pretty much the Grandaddy of Western music. Also remember that all this theory is only guidlines. They are not rules, only tools to be used to lead you in the right direction to get the sound you want out your instrument.. You can make your own scale if you like by throwing a combination of notes together, although whether others will use/like it is another story.
If you're in the mood to learn some music theory, and don't mind reading "dry" material, I highly recommend Walter Piston's "Harmony". It's one of the best book on music you'll find. There's a lot in there, so just take it a bit at a time, and let it sink in.
Sorry for the long wind. Hope this helped a bit.
