The Satchel of Helpful Goods is a level-scaling bag o' rewards, which EU Community Manager Wryxian says will contain one piece each from two sets of loot rewards. Quoth the crocolisk:
...these satchels are rewards from doing a random dungeon through the LFG tool at lower levels. There's two groups of items that can be inside them. One includes bracers, rings, necklaces and cloaks. The other has belts, boots, gloves and shoulder items. What you'll find in the satchel is one item from each group, and this is also further influenced by a ten level range. So for example, what is in a satchel received for completing a dungeon between levels 20 and 30 might be a nice necklace and some gloves, but from a dungeon between 50 and 60 you might get a ring and some new boots.
The level ranges he refers to are 5-15, 15-25, 24-34, 35-45, 46-55, 56-60, 60-64, and 65-70. Wryxian indicates that the two item groups are set up so as not to trivialize quest rewards from the zones in your level range, and to make sure that you're always receiving a variety of gear. It's unknown at this time whether these'll be blues we've seen before, a la Elven Spirit Claws, or whether they're newly-created blues with the express purpose of being Satchel rewards. Still, pretty cool. Oh, and you get money too.
Patch 3.3 is the last major patch of Wrath of the Lich King. With the new Icecrown Citadel 5-man dungeons and 10/25-man raid arriving soon, patch 3.3 will deal the final blow to Arthas. WoW.com's Guide to Patch 3.3 will keep you updated with all the latest patch news.