Let's all vote......I say it is a cloth guide. does not sound like a cording foot or a rolled hem foot. Here is a site that shows an assortment of sewing machine feet.
http://www.joann.com/catalog.jhtml;$sessionid$CFK3ARQAABW50P4SY5KRIHR50 LD3UEPO?CATID=156469
this should help everyone identify all the things in their tool boxes. Be sure to continue on the next several pages. Lots of goodies.