When you open the flood gates, expect a flood.
Yesterday's announcement of PvE to PvP transfers being available for the first time in World of Warcraft brought a screaming horde (and Alliance I'm sure) of people wanting to taste the previously forbidden fruit. The reaction was so vigorous that for at least five hours the account maintenance section for the transfers was in a "Too busy to respond" mode.
As of this morning, the transfer page is available but what was supposed to be a three approval process is still showing as ten hours (16 hours later). This should not be a huge surprise as Blizzard seems to have a knack for crushing their own servers. They will get this sorted out and carebears will be flooding the PvP servers soon.