I've pretty much stayed druid throughout beta and retail, dabbling here and there with other classes. I could always be wrong, and if you KNOW I am, please correct me and list intellegence.
Druids can train in Hand to Hand, 1h Mace, 2h Mace, Staves and Daggers. Druids can only use Leather and Cloth as armor. And, Druid CANNOT use a shield or duel-wield. There are, however, off-hand items that the druid can use.
As you may know, Druids are a mana dependant class, and there are no spells that I've learned that replenish mana. There is one quest item for Druids that you can hold in your off-hand that will restore mana upon use. The item is available to young druids, so using your offhand will be realistic - just don't hope to use a shield. :)