Yes. The Nikon D40x has a hot shoe on top of the built-in pop-up flash. Be sure to check the compatibility of any external flash unit that you attach to the camera. Note: The question was changed after the first answer was posted, so that the two do not match now. An approach to the new question is that a Nikon D40x is an entry level DSLR, and you may want a flash in that price range. Suitable units are marketed by Nikon, of course, and by Sigma, Sunpack, Vivitar, and Quantary. Features vary with specific models, so you will want to investigate the features-per-dollar for the various units. [spelvin]
Yes in non i-ttl auto and manual
Yes but only with manual focus.
i bought one....doesn't appear compatible
Yes. Be aware that it is a manual flash, so you have to set the power settings manually.
Yes including: Automatic Balanced Fill-Flash (with AF Nikkor lenses/Standard TTL Auto including Programmed TTL Auto.
Generally yes, but there are exceptions. It depends on the specific flash.
Actually no they won't. I don't konw alot about canon cameras. but one thing I do know is that it prabably won't work. Just get a Canon flash or a Sigma flash.
Yes it does with non i-ttl auto (2 different f stops) and manual.
Yes, it will fit. However, you will still need to see if the lens you have has or does not have features like autofocus or CPU connectors that will carry all the info that your camera needs... If it is a Nikon Lens it will work fine. So will others like Sigma, Tamron and Tokina. Carl Zeiss may not give you all the functions but will work in manual mode.
Yes it does just got one in the mail today. Tried it out and it works fine.
nikon or keh
I have this camera, and I also have the SB-24. I have tried to work them together, and it just won't work. The Sb024 would zoom in relation to the lens focal length, but it does not do this, and the firing of the flash would not work. Save it for your old Nikon - like an N90s or something similar. It's worthless on this digital body.