where are the kernel sources?

Hi, I have got the iSub and ISDN USB modem working with the very generous help of someone from the USB list but have only been able to patch the 2.2.16 sources because I installed 2.2.18 via a SUSE RPM. I have tried to find the sources for 2.2.18 on the SUSE ftp site but can't fine them. Please could you let me know where to get the 2.2.18 sources from. Thank you. If anyone want to know how to get the iSub working, feel free to get in touch. Joss -- joss@josswinn.org http://www.josswinn.org