Update - 1.5_02 (Server only update)

[Mafios_X]

Bug Fixes:

Game no longer crashes from "internal server error" created by bugs in 1.5_01's Server in SMP
Players no longer get the "dirt screen" when taking something out of the Crafting Table

New Bugs:

Placing Rails in North/South direction, followed by placing a piece of rails on the side (and thus making a curve) results in no curve.
"Outside" rain sound still plays when under a glass shelter. In addition, Wolves under a glass roof during rain will be perpetually stuck in the "shaking" animation (unknown for multiplayer, unknown for SP)
During rain in SMP, the server may disconnect you if you attempt to place or destroy blocks.
Sitting Tamed wolves that were tamed before 1.5_01 and are pushed into water or water runs over them will start to jump in place, keeping the sitting stance, and are no longer able to be told to stand, thus continuing to do this until hit, which will cause them to attack you until death on either side. This can be fixed by closing and reopening minecraft, or killing the wolves off and taming new ones.
If you are killed while having the chest GUI open and you transfer items from the chest to your inventory after you are killed, those items will be lost.
Minecarts on fire can no longer be put out by nearby water.
When a Powered Rail is placed next to a block and redstone is placed both on top of the block and leading away from the block to a redstone torch on the ground, and then the redstone on top of the block, the redstone leading away from the block, and the redstone torch on the ground are removed (in that order), the Powered Rail will remain powered without any power source.
Placing redstone torches on top of blocks that have a Powered Rail coming away from them only seems to affect the proper number of Powered Rails if the Powered Rails have been placed prior to the redstone torch. If any Powered Rails are removed with the torch still on the block, this behavior persists.
Dropped blocks are not being ejected upwards.
Buttons cannot be placed on glowstone.