Rentmyhomefast.com is an easy to use nationwide rental listing site. It is not free, listings start at $19.95 but they offer tenant screening services as well as online photo placement for your rental property. All listings are also exported to Google base so you dont have to place your ad in multiple venues. The site is for indepentand homeowners and property management companies. Check it out at http://www.Rentmyhomefast.com
Try http://www.jicka.com. It's a new start-up company that has more features than craigslist and since it's new, and free, why no come on board at the beginning. Also, if you use a Realtor to list it, it doesn't cost you anything in New York to list as the tenant pays.
On Trulia only agents and brokers can list.. List it with a brokerage and it won't cost you anything..In addition the agent can run a credit check and show the apartment at no charge to you..The usual rental charge to the tenant ranges around appx 6% of a year's rental for a 3-6 month rental and 15% of a year's rental for 6months or longer. Let me know if you'd like a referral to a local agent
If you own the rental, Craigslist is free as well. You can also post in http://www.KIJIJI.com and http://www.flyrig.com. Let's not forget the New York Times but this is a bit pricier and is not realy neccessary if you use all of these options.
The easiest will be to put an ad on Craigslist. Adding some pictures of your apartment help.
You can also assign the rental to a real estate professional. He?she will put not only ads but will sreen the prospective renter and conduct a credit check.