I searched the net high and low for a Windows 98 CD-ROM boot sector because my install CD was never bootable. I couldn't find one anywhere.
For all the people out there like me who need a bootable Windows 98 install disc, here is the boot image. It should work with most CD writer programs if you use the default settings. I like Nero, so you just tell it you want to make a "CD-ROM (Boot)" and then in the section where it asks for the boot image, use this one. Disable the "expert options" for the boot image.
You may need to edit the image and adjust it for your particular Windows 98 distribution. If you do, then I recommend WinImage. Google around for it. It's great. Don't panic if you get the "Setup files not found" message when booting either. The FINDCD program that it uses doesn't always find the CD-ROM, but the driver should be all loaded up, so just switch to the D drive or whatever the CD drive happens to be and run setup manually.