ltspice runs well on wine... once in a while you get artifacts when using the wire draw tool, but they go away when you exit the tool.
Gschem is ok... there's also kicad for linux and i like that too. i like it better than gschem because it seems to translate a schematic to a pc board much easier than the geda tools do. there are also some scripts for creating new schematic symbols from a pin list or even pictures of pin layouts for QFN, QFP, and BGA chips.