The pronunciation is indicated in IPA. The sounds are best learned from a native speaker. Whenever possible, practice these with a native speaker. Reading aloud will also help your confidence. Note that the Norwegian language is full of dialects, so there are several ways of pronouncing the words. Foreign learners are usually taught to speak the way that people in the Oslo-area speak.
The main rule is that long vowels occur before single consonants, short vowels occur before double consonants. This is no absolute rule, though, as you will see in the examples below. Notice: the short o sound is actually never to be found written with an o! (It's usually represented by u)
These are also quite equal to the English language, except that Norwegian does not have θ, (as in thin) ð (as in this) ʒ (as in measure) and z, (as in zing) but at the other hand, norwegians have the ç sound, which is sort of a stiffer version of the ʃ sound (as in German ich)
Norwegian has two contrasting tonemes. These are kind of hard to describe using text, and some also say that foreigners (to Norway) are even unable to distinguish one from the other. However, they do exist. In the words indicated with 1 and a hacek, the tone is normal in the first part of the word, and rises in the last part of the word. In the words indicated with 2, the word is pronounced like any other normal word. (In other words, it's very hard to say 1 words in a monotone voice) Here are two examples:
Notice: The two last examples are very similar to each other even though they are different, and I am actually somewhat unsure if it's loven or låven which is the more "special" one.