hi guys

i know that al is a contraction of a + el and basically means "to the" but i've been using this Spanish learning software and they use it like this:

Al muchacho no le gusta el sombrero

is this correct? if so is there a reason they used al instead of el?

thanks for any help

Yes, that is correct. A transliteration of that sentence would be:
To the boy it is not pleasing the hat
Now let's flip the synax around so it looks more like English....
The hat is not pleasing to the boy.
In English we use "to the boy" and in Spanish it's "al muchacho". So with the verb gustar, you pretty much always have to use "a" to tell who the thing you're talking about is pleasing to. Of course you can leave out the "who" completely:
No le gusta el sombrero.
¿A quién?
Al muchacho/A él.
So just to practice a bit, I'll give you some more examples.

The whole "a mí, a él, al muchacho, a la muchacha" thing is only used if needed to carify who you're talking about.
Me gusta esto.
Esto me gusta.
El otro me gusta más.
No le gusta esta música.
Esta música no le gusta.
A mí me gusta esto.
Esto me gusta a mí.
Esta música no le gusta a él.
A él no le gusta esta música.

Anyway, that's my take on it. Anyone else want to comment? I think Sosia would give you a better explaination than I could. :)

I'm not a expert, so your explanation is perfect. I only give this one
a/de + el as article --> al/del
"Vino del monte y se va al río"

a/de + él as personal pronoun --> a/de + él
"Se alejó demasiado de él y por eso no puede acudir a pedirle dinero, precisamente a él".

thanks for the help guys!.

I just wanted to add to what sosia's saying about when the "el" is a personal pronoun, there is no contraction with the "a". That's perfectly true, and I just want to add one more scenario where the "a" is not contracted, and it's when the "el" is part of a proper name such as "El Salvador" --> Voy a El Salvador.