POSTING AGAIN
No need to post here requesting Dual Speccing. The Devs are adding this. See the link below and I've also pasted the Q&A from the article:
http://www.swtor.com/news/news-article/20110916
Q: Since it has been clearly stated that there will not be dual specs for characters in the game, can you explain your philosophy behind the skill trees and how you are taking into account players that want to be able to play PvP and PvE content on the same character? - illumineart
A: Dual Speccing is something we want to add soon after launch. Also, features like Guard, PvP Taunt, Resolve, etc. work to narrow the gap between PvP and PvE specialized skills (i.e. a +Block skill would be helpful in both PvE and PvP).