Alas, I Can't help you with the CDROM boot thing. WSP's bios is finnicky like that. I Suggest getting a WSP mod kit, and use the onboard IDE. :)
As for getting linux on board, here's where I've screwed up the most: When you install it on another machine, generally it will install a kernel for that specific CPU series. (in my case, I installed it on a PIII/550 Xeon) I pulled the drive out of the PIII, put it in the WSP, got a kernel panick. Solution? Recompile the kernel! I know it sounds evil, but if you search for "Josh's Linux Guide", he wrote a very nice piece for beginners on recompiling.
I'll save you the trouble of finding out WHAT to change though.. When you type "make menuconfig" (Xconfig and config are too confusing for most, I've found), there's a section called "Processor Type". Select that, and make sure you compile the kernel for 586. (not 686, PIII, or anything funky like that.) Also, enable Kernel Math Emulation, since the Cyrix math coprocessor isn't all that hot. That should get you goin' with a bootable kernel.
If you're using Loadlin from dos, and getting a VFS error "unable to mound /root", then I can't help ya. I never got past that either. If course, my IDE controller is an old ISA one I pulled from a 486.
That's another thing.. if you have an old controller, it probably doesn't even support ATAPI, and you're wasting your time trying to boot off of it.