The new dyes are crafted as follows: Red from red flower, yellow from yellow flower, green from furnaced cactus, blue from the new lapis lazuli ore, and white from bones dropped by skeletons. Black comes from ink sacks dropped by squids, new friendly underwater monsters. You can mix dyes to make orange, cyan, purple, grey, light blue, pink, lime green, light grey and magenta dyes. Cocoa beans produce brown dye, but there are no cocoa beans yet.
There are also black, dark grey and light grey sheep, who drop that colour of wool. You can dye sheep, and when you shear them you'll get that colour of wool.
Items are given official names now. Gunpowder is actually sulphur, hellstone is now netherrack, slowstone is soul sand, mossy cobblestone is moss stone, stone halfblocks are stone slabs, and adminium is bedrock. The watch is called clock. Log is now wood, and the block created from it is now known as wooden planks.
Four sand can be crafted into standstone. Furnacing wood log turns it into charcoal, which works like coal except it's a renewable resource. Charcoal can be used to craft torches or used as fuel in a furnace.
Can spiders climb along a ceiling? If not, a one block outcropping at the edge of your wall should sort them out. I'm glad I lined the edge of my castle with burning netherrack.