ShardWatch is a simple, easy to use addon for WoW 4.0.1
It watches the 3 available soul shards for warlocks, in an easy to read display.
With ShardWatch, you can easily see how many shards you have left. You can click/drag it anywhere you'd like, and can resize the size of the shards. Just type /shardwatch in game for a list of commands.
fixed slash command (/shardwatch and /sw should both work now)