I just have to give you a word of warning, it will be pretty hard finding a property here, especially for 3 months, but people somehow manage. The rentals this year are really hard to come by. You might ask your employer here if they have employee housing.
Wells and Bennett, Tahoe City
Housermann Rentals, Tahoe City
and then private rentals on vrbo.com, and craigslist.org (search for Reno/Tahoe).