Since there's some interest, here's a quick overview of the 8 races in the 3D game. There are dozens in the Java (and board) version, but I'll not go through all of them. There's a guide to them all
here anyway.
Human
Humans are versatile teams open to any tactic. By weighting your player selection in a particular area you can choose pretty much any type of play, even using several in the same game. With tough linemen and blitzers, skilled throwers and catchers, fast runners and huge ogres, Human teams can be tailored to suit any coach's preference or overcome any opponent.
Lizardmen
Lizardmen are very fast, suited to the running game. Unlike some other running teams, they also have a good choice in tough (but also fast) linemen. However, they can be delicate. A Lizardman team should play a mobile game, taking advantage of the fact that even their slowest players are faster than most, finding holes in the opponent's defences and exploiting them to outrun their opponent to the touchline.
Dwarves
Dwarves are slow but extremely tough. The team is weighted towards surrounding the ball carrier with linemen and tanking their way to the opposing line, destroying any opponent stupid enough to get in front of them. Dwarven teams are rarely high scorers, but once they have a solid defensive line they don't need to be as scoring past them can be extermely difficult.
Orcs
Orcs are a tough but versatile team, favouring a brutal charging game but also able to run and throw. The basic orc lineman can quickly punch through an enemy defence and capitalise on it by shielding the ball carrier to the touchline. While the basic blitz tactic will work perfectly well for the Orcs, they also have reasonable throwers and catchers, and access to speedy goblins to dabble in the running game.
Skaven
Skaven are one of the fastest teams in the game, able to exploit small gaps in defences and race to a touchdown. They suffer from being rather weak, though, with very little in the way of strong defensive players. For the Skaven, the best defence usually involves stealing the ball and turning it into an offence.
Chaos
Chaos teams are vicious fighters, and are capable of causing a lot of damage to an opponent. While not hugely skilled, they can often win a game just by destroying the opponent before walking to the touchline.
Wood Elves
Wood Elves are skilled ball handlers and fast runners, playing the passing and running games well. However, they are very delicate and can quickly become crippled by injuries. A good Wood Elf player can run rings around an opposing team, outpositioning them and throwing the ball over the defence.
Goblins
Goblins aren't the strongest, the most skillful, or the fastest race on the Blood Bowl field. They are the dirtiest though. Their low cost means they can absorb casualties by having high numbers, and their relatively high speed allows them to get around the pitch. However, they have little skill with the ball. The main advantage of the Goblins is their ability to create havoc. Bizarre illegal weapons (chainsaws, pogo sticks, huge ball-and-chains) and blatant fouling are all part of the Goblin game - even more so than actually attempting to score. Should they consider scoring, the Goblins always have the option of taking a troll who can hurl his teammates down the pitch.