When do I use the definite article (teen) and when don't I?
In general, when you need to reference a specific item (the tea, as opposed to a tea). Same as in English. The other times are when you're using the possessive forms, such as "teen min/my tea".
Do they have iced tea in Norway?
Not really, and it makes me sad. :(
té is technically correct, no? It seems that every time I put té it says it's a typo, but that's not true is it?
It is "te", not "té". The acute accent is usually used to indicate that the stress is not the first syllable as is the norm in Norwegian. That is not the case for "te".
vi gjore det også !
Jeg liker te med sitron!
Hvorfor det må vi drikke te med øl?! Hva faen!!