The ipod connector will recognize and connect to most dSLRs.
However it will not reliably download data.
It works for some "compatible" P&S cameras but not all and not consistently.
As the ipod can be used as a data storage device, albeit not readily and
using methods Apple does not publicize, when attached to a computer I cannot
understand why someone else has not marketed a card reader that will work
reliably and upload at the speeds the ipod is capable of writing data, which
is quite reasonably fast for a device of this type. The card reader could
even be battery powered.
There is absolutely no technical barrier to immediately producing such a
device.
I presume Apple will not allow such a device as it might change the
expensively marketed image of the ipod as a cool multimedia device to what
it really is: a tiny form factor hard drive with a very cleverly designed
control wheel that is saddled with an antique, closed operating system only
a monopolist like Apple could love.

I have a 30GB video iPod and am considering the camera connector for
offloading images.  My experience is that I've googled it to death.

Apparently, yes.  The copy operation is very slow.  I've seen it
consistently reported that copying a full 1GB card is in the vicinity
of draining a fully charged iPod battery.  If the copy doesn't finish,
you cannot just recharge everything and restart the copy where it left
off.  It will start over from the beginning unless you manually clear
stuff out of the card first.  The camera connector appears to be
useful only if you can limit yourself to somewhat less than a GB of
images at a time and if you have ready access to power.

The iPod plus camera connector won't do what you need if you can't find
power.

It's hard to imagine why it wouldn't just work with any camera that
implements the usb_storage model, but you will find lots of reports
both that it works fine and that it works unreliably or not at all
with some cameras.  It's sometimes hard to distinguish an unreliability
report from an "It ran the battery down and I couldn't figure out how
to recover" sort of report.

This might work if the card reader had its own battery.  The real hard
limit is that the iPod only has enough juice onboard to transfer a bit
less than a GB.  If you add a card reader to the iPod's current drain,
you just hit the wall sooner.  I don't recall seeing reports of anyone
hooking a card reader to the camera connector.

I shoot 8Mp JPEG's, and can generally go many days on a 1GB card,  I
figure Apple's camera connector would be useful on a trip lasting more
than two weeks where I had at least sporadic access to power.  If I were
going on an extended trip off the grid, I'd probably just buy more
memory.  It's cheap lately.

Paul Allen