Is a Nikon D40 camera good for beginner?

I want something that give high detailed pictures

Yes, it's fine. Of course, there are much cheaper point and shoots that will give highly detailed images.

Never choose a point and shpot over a dslr. It's alright but I recommend a used d70s or a d5100

Great camera, just out dated. It was replaced by the D3000, and that replaced by the D3100. I suggest one of those instead.

Yes. There are plenty of people I know online that are still shooting away with the old D40. I'm on a Flickr group for D40's and D60's and the newer models. If your buying used though, you need to know what the shot count is at to give yourself an idea on how many shot may be left to take with it. Just my personal preference of wanting to buy a new camera so I know how it is treated though. If your like that too, try a D3100 or a D5000.

Sure and one of the best entry level DSLR. As long as you can still buy it. You can upgrade later to D7000 after 3 years.

The Nikon entry level that can outperform it in some ways is the D3100 after 6 years the D40 is in the field. Take the D3100 if you want a more advance level entry but the D40 is just good enough for a beginner.