Why does image become blurry when I zoom in?

I recently got a Nikon D3000 Digital SLR and I'm still figuring it out. When I zoom in the image becomes blurry. This even happens when I've used a tripod. How can I correct this and make the images sharper?

-Better focus
-Higher quality resolution
-Better exposure
-Low ISO's
-Fast(er) shutter speeds
-Good glass (high quality lens)

A link to a flicker copy of the image would have helped since we could have looked at the EXIF info on the image.

Here are some guidelines. You need to shoot faster than your focal lenght… I know, it sounds like Han Solo bragging about how fast his ship is by telling people a SPACIAL measurement instead of a TIME measurement.

The thing is that when you press the shutter release, the camera shakes. This shake causes blur since the lens moves. The best way to reduce that blur is to shoot quickly. The longer the focal lenght, the more "shake".so if you are shooting at 200mm then you need to try to shoot at at least 1/250th of a second.

Also the faster the action in the scene the faster you need to shoot to freeze the action.

Without seeing an example with EXIF info intact, that's all I can offer you.