How do I handle an interrupt? Just need simple example..

I have an ISA card that my company has produced.
Every so often it makes IRQ10 happen.
I need to write a byte to an IO address (0x230 I think) when this
happens, and also an application I am running needs to notice.

This sounds like it should be very easy to do.
But I can find no information on how to go about it on the web.
Can anyone explain it to me, or point me at a decent tutorial?

I have the XP ddk, so if a tutorial exists in there I can use that
(I've seen various general driver tutorials, but they seem very
complicated, e.g., "here is how to write a pnp pci printer driver", and
all I want is a small simple example of how to handle a specific irq).

I found this
http://www.codeproject.com/system/interrupthook.asp
which looked good, and was proposing to use the same method the author
of that article to get a handler to be called, and then set a named
event when the handler was called. My other code would then notice this
event and take some action. But the author says this is the wrong way
to go about it.

I do not need to share the interrupt with anything, and I can live with
a fair amount of latency (of the order of half a second!). Also it is
always IRQ10, so I don't need to PnP or anything (it is an embedded
thingy, so I can get away with quite a bit of hardcoded nastiness.
The card is an ISA card if that makes a difference.

I've 10 years experience as a professional c++ windows embeddedish
programmer & have written CE.Net USB drivers & things, so I should be
able to cope with fairly teched answers I just don't know lots about
xp internals and have not done much drivery stuff before.

TIA,
5thWheel