How can that be, you say. Enhancement's for leveling, not for raiding! Kessin of the Dark Iron server would beg to differ and to prove his point, he wrote up quite an excellent guide to playing an enhancement Shaman from creation to Karazhan.
The first half of his guide covers what you need to know to get from level 1 to the front door of Karazhan. He includes this sage advice: if you guild doesn't want you playing weapon wielding, totem throwing, whammy shammy, then get a new guild. In my opinion, this goes for every class working with an off-spec. Skill and talent trumps cookie cutter spec every time.
Once in the 10-man raid zone, the guide gets interesting. Kessin provides the strategy for this spec for every major boss fight. Don't worry, all you hardcore raiders, Kessin also recommends off healing when necessary. If you love your enhancement shaman, or play with someone who does, this is the guide for you.