Win 7 is included in the list of OSs for the Windows platform for the latest LW version:
Get LimeWire for Your Platform - Lime Wire
You might find some more info here (click on link):
LimeWire Forums
Check out the LimeWire 5 and Bugs & Beta Testing sections - I think some Win 7 users have posted there in the past.
Since you're posting in English, I'll move this out of the espaņol section