To get to the spider dungeon, type in the following words (Caps and spaces included). "Double Buffered"
Once you spawn you should be on top of sand and see an island of dirt and very few trees appear infront of you. Turn right and you should see a huge clump of land in the distance with exposed stone.
Make your way on top of it. Once on top of it there should be a desert biome to your right. Go to it, but continue in the same direction that you were headed before you saw the biome.
If you are going the right way, you should soon hit an ocean with a bit a gravel and a few blocks of grass in it with another island in the back ground. The island should have very tall and pointy tipped mountains on it.
Head on over to that island and try to stay on the left edge of it once you are walking on it.
Proceed to continue until you reach an extremely deep hole with a lava fall and a waterfall in it.
Once you make your way down you will be confronted by two paths. Choose the path that doesn't have the gravel at the begging which is also the one that ascends upward.
Keep following it and you're done you've found the dungeon! :biggrin.gif: