Ah, Minecraft. Every time I forget about you or get sidetracked by some new game coming out, you remind me why I keep coming back to you; the neverending updates and changes. Even though Beta version 1.5 just recently came out introducing a dynamic weather system among other things, some information on what lies in the future was released today on Notch's blog.
The team is working on implementing a mini-map tool. Players will make a new map which will start off empty, and map itself as you explore. You'll be able to pass this particular map to other players, and a way to link maps (and possibly use it to locate friends when online) might be possible.
In addition it looks like the team is working on implementing a recent popular mod into the game, the Piston Mod. This creates a special block that when activated raises it's top one block, including anything that's standing on it. It's hard to explain, so watch this video for more details and to be amazed. Hidden bookshelf entrance? Self-repairing bridge? SECRET bridges? Oh man, this is going to change everything.
For more information on these be sure to check out Notch's blog.