Happy Monday Tammy, You may list your availalbe lease on the MLS. I've also found craigslist.com to be a very beneficial (and free) form of advertising the lease. Equal Opportunity Housing rules and regulations apply.
The pennysaver also lets you advertise on-line for free, but I've never recieved a response from them. I also got a lead off of WestSideRentals.com (another free advertising site).
Good luck. I hope you get it rented soon.