I'm new to linux, and I've just recently installed Debian 3.0 r4. During the installation program I was asked what network adapter should be searched for and installed on my system. I chose the NE1000/2000-option, since I have an ISA PnP NE2000 adapter. Right after, an error message displayed, saying the card wasn't found.

How do I manually install the network adapter? Do I have to compile driver modules into the kernel? If so, how do I do this?

From my WinXP hardware manager, I know what IRQ and resource address my network adapter uses.

Anyone, please?

For ISA NE2000 adapters you need IRQ and port. You know them, so no guessing needed
You don't need to compile anything, because the right driver (module) should already be in the system. It's called 'ne'. The command to load it will be (in your case, with port and irq):
modprobe ne irq=XX port=0xYYY
For example
modprobe ne irq=11 io=0x330
It should load (read: not show any errors). If it does work, add module name with parameters to /etc/modules. It will then load at boot.