This is one of the most excellent sidequests in the game. By sidequests, I mean ones that don't send you up against ancient demons or powerful avian gods, but ones that describe the little people of WoW - in the case, one innkeeper now known by the name of 'Smiling Jim'. There are a bunch more of these, like Mor'ladim and Jitters and Magister Duskwither and so many more... I might cover them all at some point. However, today is not that day. Today, we Questes!
Who can do this?
Well, both Alliance and Horde members can do the quests, however they are fairly different and the Alliance one ends with much more conclusion.
In terms of level requirement, you need to be level 37 to finish it, and 30 to start. You might level up enough over the course of the chain, because a ton of quests coincide with the quests in this area, however it's your best bet to just wait a little and at least hit 34 before starting. Unless you plan on running dungeons/bg's in the interim. Which isn't a bad idea.
Well, finding the start for this one has to be easy!
There are like 18 different ways to start this quest, so I'll be brief about each.
Alliance: First, you can pick up the quest chain off of Connor Rivers in the Blue Recluse - the inn in the Mage District in Stormwind.
Next, you can get it from Guard Byron (No, not the extremely stealthy tauren) who's inhabiting the walls of Thermore.
Horde: You can pick up a quest from one Krog to go check out the ruins, who's chilling in Brackenwall.
OR, you can just go straight to the source, the Shady Rest Inn, and grab the three objects off of the ground and surrounding areas; The Black Shield above the fireplace, the Suspicious Hoofprint on the ground, and a little glimmering badge on the floor.
Fine. Its four. Still a lot.
Ok, got a little tricky maneuver for me this time? Huh?
Nope. Wowwiki it is. Horde has a nice wowhead post too (the pink one).
Any 1337 Loot?
Ee-yikes. I'll make it quick.
In the end, you get some Leggings of the Long Road (caster cloth), Skirmisher's Cover (Hunter/Feral Druid/Rogue cap), or a Steel-banded Hauberk (nice for warriors/pallies).
Then you get one of three: Biting Axe (Str/Agil), Bone Dirk (Many Agils and a stam), and a Glowing Tourmaline Ring (stam/Spi, eww).
Then the horde can get:
You get to choose between 2 items: Eyepoker (statless wand) and Blasting Hackbut (statless gun).
Not all that great, but not all that bad.
As with all of these... A - it rocks, and B - it could go away. However here we get to see some of the neat things Blizzard did with two different factions - if you get a chance to do both sides of the quest, you see insights into the situation that you never would get if you only saw half of the story. The Battle for the Undercity is another such quest which is explored differently on both factions (I only recently did the horde side one and was duly impressed), and it'd be neat to see if Blizzard gets to bring more such quests into Cataclysm - even in dimensions like PvP or dungeons or raids, which explored different sides to different stories or different factions. There's so much that Blizzard can do, and has done, it'll be quite awesome to see how they tinker around with things now, to get a feel for what they can and cannot do in their unannounced MMO.
Also: the alliance quest ends in a tragic yet noble way. It's one of those things that would deserve voice acting if Blizzard put the time into it (perhaps a short cinematic as well). But it's a cool quest in the constraints they have - one that really shows you what the smaller stories of Warcraft are all about. I don't know how much time they'll put into revamping Dustwallow as in 2.3 it got added to a fair bit, but who knows what can stay and what will go... when the world is devoured by rage.