File attribute problem

I have a volume where all the files have the following type attribute:
drwxr-xr-x@  11 rpeskin  staff      374 Jan 13  2010 Snow Leopard

The "@" attribute is a real problem; it prevents write access to the file or Volume unless admin authorization is supplied. I have no idea how this "@" got there; the volume (a disk partition) was created in the usual way with diskutil. How can I get rid of these "@" attributes?

--dick peskin