Well, "argument" usually implies something in the URL, which is certainly available to you [arg()]. If this is a node display, then menu_get_item() will load that node for you.
Nancy
From: Marolijo
Hello, I'm developing a module to show data related to actual node on a block. It's working and now I need to pass arguments to the block, is it possible? Something like an integer that comes form a select list. If it's not possible what's the way to do this?