Getting into trail running is easy! When you first start, normal road running shoes are perfectly acceptable. I ran for about a year on the trails in road shoes when I first started off-road running.
Once you make the decision to buy some trail shoes, it's really not very complicated. I wear Saucony shoes, either the Xodus or the Peregrines. They both have multi-directional lugs to provide great traction, grip and protection on a wide variety of terrains. The Peregrines are lower profile, increasing their responsiveness without sacrificing protection.
The main difference between a road shoe and a trail shoe is the added traction and protection. The lugs channel mud and water so you don't slip as easily, and the sole is designed to protect your feet from kicking rocks, sticks, etc.
You will also need some method of carrying hydration on your runs. I am often running in the bush for a number of hours with no access to drinking water. I wear a Nathan Hydration pack or carry Nathan hand helds. Both of these options also have pockets for some food, which always comes in handy!!
A good place to find out about trail or ultra running events are the following sites:
Of course, if you have any questions about starting trail running, please go to my contacts page and email me!