I concur that it is best to use a Realtor for selling the house. Besides the fact that buying and selling real estate is all they do, the Realtors use MLS to find properties for their buyers and Realtors talk with one another, so if a Realtor calls you, are ready for their calls, will you protect them if they bring you a buyer? If so, there are many flat-rate companies that will place your property on the MLS, then add up to 20 pictures and leave it on the MLS for a period of time.
You can also add your FSBO to many of the FSBO free sites, Zillow also allows you to create a FSBO listing and then post it in a formatted page up to Craigslist. Trulia will allow you to post your property as will a number of other sites. The more you add, the more eyeballs see you, but you need to do this.
I'll leave you with the report from Move.com, they manage the realtor.com site, they recently stated that not using a Realtor ends up costing a seller between 8-12% of lost revenue. So when you think about the 3% you would pay, you can receive between 5-9% more using a Realtor. Who can't use an extra 5-9% in their pocket?
Best of luck to you,