Pronunciation

First of all, in Spanish, there are actually 28 letters in the alphabet.

a b c d e f g h i j k l m n ñ o p q r rr s t u v w x y z

The 2 new letters are ñ (pronounced enye) and rr (erre - you have to roll the r... sorry, I can't really explain it). 

Vowels:
a is said like the a in father
e is said like the a in way
i is said like the e in we
o is said like the o in go
u is said like the oo in boo

Also, in general, each word has as many syllables as it has vowels. For example:
rosa= ro-sa
mucho= mu-cho
escribir= es-cri-bir

The h is never pronounced.
hola= o-la
ahora= a-or-a

Words with ll are pronounced as a y.
lleva= ye-va
amarillo= a-ma-ri-yo

The letters b and v sound the same. (Although when you're just learning Spanish, this isn't usually emphasized as much as the other pronunciation rules.)
favor= fahbhor
Keep your lips slightly open.

A c before an e or an i will have an s sound.
dice= di-se
cine= si-ne
A c anywhere else will have a k sound.
como= ko-mo
toca= to-ka
When you have both:
cinco= sin-ko
lección= lek-si-on

A g before an e or an i will be like an h.
general= he-ner-al
escoge= es-ko-he
A g anywhere else is a hard g as in give.
gana= ga-na
regalo= re-ga-lo
gigante= hi-gan-te

To practice saying all of the vowel sounds, try saying this phrase:
El burro sabe más que tú.
(The donkey knows more than you.)
Sorry, but it does get you to practice saying them...