Newbie Q: Where are my kernel sources?

[Chris Share <cpsmusic@labyrinth.net.au>]

Hi,

I'm trying to install HSF modem drivers for my linmodem.

In the installation instructions it says the following:

run "make install" from the top of the package directory. (Debian users 
might need to change the KERNELSRC definition in modules/common.mak first).

I tried doing this and got the following error:

"KERNELSRC does not point to a proper directory."

According to some other information I found on the web, the entry should 
read something like:

#KERNELSRC= /usr/src/kernel-headers-2.4.18-686 (depending on the actual 
kernel being used). However, when I go to /usr/src all that's there is a 
directory called RPM which contains several directories that appear to be 
empty.

Where should the kernel source be on my Debian 3.0 r1 system?

How can I locate it?

Any help would be much appreciated.

Cheers,

Chris Share