Texture packs?

[SABITRON]

Is there a way to use other textures for blocks?

[RSDuck]

if you really really want to you could download the source code of Craftus change the textures in this folder and compile it.

Your existing worlds should work fine, but keep in mind that the textures have to have the same size and be in the same format(png)

EDIT: btw almost every file is named like the respective file in Minecraft, so it should be easy to the textures by those of another texture pack(16x16!).