I've never heard of RentInRome.com, but I have been using WantedInRome.com for quite some time now.
I think the site originally began as a listings page run by British-expats living in the Italian capital, but it's now become a full-blown community project.
When I went back to Rome on holiday, I rented a room in an apartment through WantedInRome.
I initially had some misgivings because the landlord seemed a bit strange when we first went to check the place out, but in the end it worked out great - and the price was affordable and the location was great: Right next to Piramide station and the vibrant area of Testaccio.
