At EL34World you can really find a large library of schematics in SCH format
I've used sometime ExpressSCH and much more JSChem, both read SCH schematics
but if you really want to draw easily schematics with a perfect look my council is to use FidocadJ this is a FREE program that is an evolution of the old Fidocad 
With FidocadJ you can draw schematics and PCB in a very easy way
you can download it and a lot of documentation here
http://davbucci.chez-alice.fr/index.php ... ge=English
in the libraries there are also tubes and if you require a special component that is missing it is very easy to draw it by yourself and add to the library
K