Query string without ?

I’m building a site for a real estate company. I created a plugin to create and edit listings. All the listings information is stored in a database. I’ve created one ‘page’ called property that will display information about a listing based on the query string in the url.
So right now, a listing would look something like : http://www.thesite.com/property/?listing=123-main-street-new-york-ny.
I created a rewrite to take out the ?listing= so the url would just be /property/123-main-….. But when I do that, I get a page not found error. Is there anyway to have my url without the ?listing= and wordpress still think it is a valid page even though there is no ‘page’ created with the title of 123-main…. ???
Any point in the right direction would be great.

Thanks,
Greg