While elves in fantasy often represent magic and art, dwarves represent technology and practical thinking.
Dwarves have had various different faces in the fantasy settings, but the image that J.R.R. Tolkien presented us in his works has not been significantly changed by people.
While it isn't really obvious to outsiders how the dwarf society works, what is known is that the dwarf males are the part that most outsiders revere the most and see most often. When you think of a dwarf, you most often think of a male dwarf. Short, stocky guy with a beard. People often don't even have a picture of what a female dwarf even looks like. In the view shown in most serious fantasy settings, female dwarves are actually not much different than what one would expect - no beards here, and young male dwarves supposedly don't have beards either. Dwarf women and children are just not that often seen in the outside world, and often play no role at all in the games! Sillier fantasy settings go on suggesting that dwarf gender doesn't really matter - they all look and sound the same, beards and all. Dwarves are an ancient race, but they are still mortals, even though their life is usually much longer than human life.
Dwarves are, as everyone who has seen Snow White and the Seven Dwarfs knows, miners. As such, they live mostly underground in their own mining colonies, unearthing massive riches. (Again, sillier settings often go on about the usual dwarf obsession with the riches: Dwarf drinking songs that go like "Gold, gold, gold, gold, gold...") Once the mines are emptied of riches, they're furnieshed into luxurious, grand caverns that are equal in splendor to any palace in the surface. They're typically good at all sorts of crafts, only being second to elves what comes to making of weapons, armor, and jewelry. And everyone who has ever done business with them knows that they're very good at negotiating, especially what comes to getting more money. Dwarven cuisine is world-famous and dwarven drinks much more so; even though it seems unfairly stereotypical to say so, a sober dwarf is a dangerous dwarf in combat, a drunk dwarf triply so.
Dwarves are typically excellent fighters and known for their strength and perseverance. In battle, dwarves typically use axes. Dwarves are not particularly known for their magic, though, except (of course) in the craft side.
There's always been some grudges and distrust between dwarves and the rest of the world. Dwarves seem to particularly distrust elves and hate orcs (of course, everyone hates orcs, but none as much as dwarves). However, the elf relationship is more of a suspicion: dwarves can cooperate with elves if it's absolutely needed, and over long period of time, even become friends.
(Not many sources to mention, all of this from the top of my head...)
(Myth units)
So the Generic Fantasy Dwarves are miners, right? Well, Myth cuts right to the bone of the issues: Mining is primarily about blowing stuff up.
Dwarves in Myth games are the really heavy artillery that really helps your cause. Dwarves carry a lot of Dwarven Cocktails, bottles filled with explosives - essentially Molotov Cocktails that are a lot more explosive. They also carry a small number of satchel charges that are set on a place and detonated with a cocktail.
Typically, dwarves are very good at slow-moving opponents such as Thralls (a single dwarf can kill half of the huge bunch of Thralls headed your way!) and are particularly effective against Stygian Knights.
However, dwarves require a lot of care in the game, particularly because in their absolute love of gigantic explosions, they often throw their explosive bottles right among your own troops! I'd definitely place them into the front or front corner flank, in front of the archers, and tell them to get the hell out of the fray once the situation escalates into a full-blown melee between the warriors and the enemy.
Other Dwarf units include Mortar Dwarves (regrettably not entirely competent yet in the games) and ultra-super-secret Pathfinders (in the game, they're invisible to the enemy until they attack, and apparently they're also capable of reading minds to some extent...)
Since there are no elves or orcs in the Myth world, their enemies in these games are Ghôls, with whom they have had a lot of clashes, recently particularly about the city of Stoneheim.
Sources:
Gene Seabolt. GURPS Myth, 1999. Steve Jackson Games, 1999. ISBN 1-55634-413-9.
Matthew Soell, Doug Zartman and Max Hoberman. Myth II: Soulblighter game manual. Linux version. Bungie Software Products Corporation and Loki Entertainment Software, 1998.