Learn Swedish: Imorgon ska vi resa till Sverige. - Tomorrow we will travel to Sweden.

till translates to "to" and is used because there is movement or direction towards a destination. If you were already inside Sweden, you would use the location preposition i (in) and say vi är i Sverige (we are in Sweden).

Why does the sentence say ska vi instead of vi ska?

This is the famous Swedish "V2 rule." In a normal sentence, the verb must always be in the second position. Because we put the time word imorgon in the first position, the verb ska must come next. This pushes the subject vi into the third spot.

Why is the verb resa instead of reser?

We are using the helping verb ska (will) to talk about the future. Just like in English, after ska, the next verb must be in its basic dictionary form (the infinitive). So we use resa (travel) instead of the present tense reser (travels).

I've seen "tomorrow" written as two words before. Is imorgon correct?

Yes! You will see it written as both imorgon (one word) and i morgon (two words). Both are completely correct, very common, and mean exactly the same thing.