I would like to take close up photos with a digital slr camera. What kind of lens or adaptors will I need?

As others mentioned, you need some macro solutions. Here are your options:

1) Macro lenses. The most expensive, but probably the most effective solution. Macro lenses are incredibly sharp and well worth the value you pay for them. These lenses are available from almost every major lens manufacturer (Canon, Nikon, Sigma, and Tamron, just to name a few).

2) Extension tubes. These go between the camera and your lens, and will reduce the minimum focusing distance of that lens, allowing you to focus closer to an object. Kenko makes a good set of 3 extension tubes for $150-$200, so more cost-effective than a lens.

3) Close Up filter attachments. These attach onto a lens and basically magnify the image in that manner. These are sold at various diopter levels designated by a + sign (+1, +2, etc), and are probably the cheapest solution of the three. However, since these are filters, you have to ensure that they fit the lens you plan to use it with. So, if you have more than one lens, check the filter size of the lens (usually printed on the inside of the lens cap), because you may need more than one size of these filters, so costs can add up that way.

see link

http://en.wikipedia.org/wiki/Macro_photo...

You would need a macro lens to do this.

It depends on just how close you need to get. Usually the standard lens will focus properly down to a few inches in its Macro mode. Check your camera's specs.