Is the Wide angle converter (Nikon Wc-E68) compatible with the D3000?

You need to use a card compatible with the D3000.

The D3000 works with SD cards (up to 2GB) and with SDHC cards (up to 32GB). It does not work with SDXC cards (larger than 32GB).

This is the tripods and monopods forum, perhaps you would have more luck posting in the camera lenses forum.
Hope this helps

You don't "set wide angle." Wide angle is not a function of your camera, it is dependent on the lens you use on your camera. You need a lens with a low focal length such as 24 mm.

Yes. The smaller sensor of the D3000 will make it the equivalent of about a 105-315mm lens on a 35mm film or full-frame digital camera. Also, the autofocus will not work with the D3000.

hi there, Nikon D3000 only support lenses with built-in motor
if you want to use this lens, you can only operate it manually while focusing on object
hope this reply will help

There are a lot of good books. What's best for you would depend on many factors, including how much experience you have or don't have with photography in general and with other Nikons or SLRs.

Below are some recommendations. You might want to browse through a good bookstore and take a look at some of them.

David Busch, "David Busch's Nikon D3000 Guide to Digital SLR Photography"

Julie Adair King, "Nikon D3000 For Dummies"

Jeff Revell, "Nikon D3000 : From Snapshots to Great Shots"

Jon Sparks, "Nikon D3000: the Expanded Guide"

J. Dennis Thomas, "Nikon D3000 Digital Field Guide"

Darrell Young, "Mastering the Nikon D3000"

In addition, there is a free video tutorial on Nikon's web site:
http://www.nikondigitutor.com/eng/d3000/index.html

ALL Nikon AFS branded lenses are compatible with the D3000. The AF lenses are usable in manual mode. Sigma, Tokina and Tamron lenses without the built-in motor are manual mode as well.
To be sure, check the manufacturer;s websites.
Hope this helps,
Andrew

For the best results, you should always employ a professional photographer

This lens was manufactured by Kino (aka Kiron) made in 2001. I will try to find out it's compatibility list and post it here when I have it.