Hurrah! it seems that Samsung have finally chosen to release drivers for these robust printers for Windows & in both 32 and 64 bit flavours:

http://org.downloadcenter.samsung.com/downloadfile/ContentsFile.aspx?CDSite=US&CttFileID=2504432&CDCttType=DR&ModelType=N&ModelName=ML-4500&VPath=DR/200910/20091021101214984/ML-4500_Win7.exe

Good news as this saves messing with the archived Vista versions!