This may be old news, but perhaps it will be useful to somebody.
I just bought a CoolScan LS-30 on e-bay. The seller sent me this link for a page on the Adaptec site. The page includes several versions of something that works as a driver for the SCSI interface card, although they don't call it a driver. They call it an "ASPI platform". I don't know how the seller found this. I certainly couldn't.
I'm not a computer expert and don't exactly know what's going on here, but I downloaded the latest version of the "ASPI platform" and it does work on my Windows 2000 Pro, Service Pack 4. The Adaptec site says it will also work on XP. The SCSI card for this CoolScan is an Adaptec 2903B. The "ASPI platform" will probably work on other SCSI cards, but I don't know which ones.
The driver for the scanner itself appears to be included in the Nikon Scan software that comes with it. I installed the software, turned the scanner on, and rebooted. Windows went through its "new hardware" routine once and was satisfied, and the scanner worked.
The Nikon Scan 2.5 that comes with the scanner seems to work OK. The latest Nikon Scan software (3.x) is available on Nikon's download site (about 16 megs). This version might require a firmware update for the scanner. When the Nikon Scan software starts, the firmware version of the scanner appears in the top title bar of the scan window right after the name of the scanner. If it is not the required 1.3x firmware, that firmware update is also available on the Nikon site.