What lenses are compatible with the Nikon D3100?

I'm looking to buy a lens for my Nikon and i was wondering if this lens was compatible with it.
It's a Nikon NIKKOR 55-200mm f/4-5.6G AF-S DX VR IF-ED Lens

I'm a newbie to photography and i haven't learnt all this yet.

Yes it is. All Nikon lenses marked AF-S will autofocus on your D3100. Nikon AF lenses that are not marked AF-S will attache, but you will need to manually focus them.

Here is a complete guide to Nikon lens compatibility, but as a general rule, ANY AF-S and AF-I lens will work perfectly fine with your D3100

http://www.kenrockwell.com/...y-lens.htm

Here's a full list of compatible lenses, including the new Nikon 50mm AF-S f/1.8 just announced today.
http://en.wikipedia.org/...ocus-motor

Your Nikon 55-200mm, being an AF-S lens is perfectly compatible and is often packaged with the D3100 as part of some kits.