Xinhuan of WorldofWar.net has done a really well done article on travelling between the different start zones of WoW.

This guide gives detailed instructions and pictures for players to travel from one starting zone to another. The 8 races of the game currently start in 6 different locations in the world, and players and friends might want to travel from their starting zone to another starting zone to adventure together. This guide shows you how.

The full article can be read here at WorldofWar.net.