Silk Cloth

A fine cloth made from silk.

Source
Silk Cloth is dropped from any number of mid-level humanoids.

As an ingredient
Silk Cloth is used in the following recipes:

Blacksmithing

 * Solid Weightstone

Engineering

 * Discombobulator Ray
 * Goblin Jumper Cables
 * Solid Dynamite
 * Iron Grenade
 * Flash Bomb

First Aid

 * Silk Bandage
 * Heavy Silk Bandage

Tailoring

 * Bolt of Silk Cloth

As a quest objective

 * A Donation of Silk
 * Hand in 60 Silk Cloth to a faction quartermaster to gain Reputation

Places to farm

 * Lvl. 25+: The dungeon city of Gnomeregan, which is Northwest of Ironforge. Dropped by any humanoids in the dungeon and instance.
 * Lvl. 25+ Riverpaw gnolls in the Stockade drop silk at 41% per mob.
 * Lvl. 25+ Bloodscalp trolls in Northern Stranglethorn drop silk at 24% per mob, and can be soloed 1 at a time
 * Lvl. 27+-29+ Stromgarde Keep in Arathi Highlands are filled with monsters that drop 1 - 2 silk.
 * Lvl. 29+-33+ The area surrounding and inside the Scarlet Monastery is loaded with silk. Many 'Scarlet' mobs drop more than 1 silk per kill on average.
 * Lvl. 32+-35+ Razorfen quilboar in the Razorfen Kraul drop more than 1 silk per kill on average.
 * Lvl. 34-40+ The Grimtotem clan in Dustwallow Marsh also has loads of silk with drop rates ranging from 72%-116% per mob.
 * Lvl. 41 Eastern Plaguelands: The Scourge and Risen mobs in general drop silk every 1-2 mobs.