I will keep adding misc. info that I find on the fan sites to this thread.
To keep things simple, Blizzard gives us just one cheat: We start from the same location, the Dwarf starting zone of Anvil Marr. In actuality, all races will have their own starting zone, so the Dwarf and Night Elf would have had to trek a-ways to find each other. (The game's built-in buddy and e-mail functions, however, allow you to invite players instantly into your group, no matter where they are.) To keep things consistent with the strategy games, by the way, Alliance races can only group with other Alliance players, and the same goes for the Horde. Early reports that an Orc player may be able to group with a Human, for example, have proven false.