Did you know Jeb is working on Minecraft Pocket Edition too? Well today he posted the screenshot above on Twitter, revealing the work on stairs and slabs he has done in the game. But looking at clues off the center of the screenshot reveal clues that Jeb didn't mention directly. First, the stairs in the right side look as if they are Sandstone, Stone, and two new blocks that appear to be Nether Brick and possibly Marble. So we can assume that Nether Bricks and Marble (as well as their stair/slab equivalents) are coming in the next update. A third change is the the touch arrow controls, which are smaller and less rounded. This could mean more GUI changes are coming as well. This is only what we can piece together from one screenshot, but it's still extremely promising.
Update: Another tweet from Jeb reveled three types of Marble, Stone Bricks, and Sandstone coming to Pocket Edition as creative-only items.
Source: Twitter