Lego Mindstorms RCX RIS 2.0 IR tower Windows 7 / XP driver
I have the RCX IR tower setup and working on my Windows 7 laptop.
I downloaded the drivers from the ROBOTC.net site here (labeled 'RCX Device driver')

Direct file download link

Note: I am running Windows 7 32-bit, according to the ROBOTC site, this driver is 32.bit only and 


  No known 64-bit driver is available for the RCX.