How do you sent a letter North Korea from U.S.?

Address it, take it to the Post office. ask them for the appropriate postage, and deposit it in the "out of town" slot.

First Class mail. Put an address on it, and a 98 cent stamp for up to 1 ounce. Drop it off at the post office.

Send the letter as If Elvis wrote it. You wont have a problem.

brooklyntalking.blogspot.com

You to south korean border,

attach letter to a rock

throw rock over border

run like hell

Doesn't sound like a smart idea.