I have Altium and it is pretty good but very expensive. They used to have a FREE version of the old DOS version called Protel PCB but it may be old and difficult to run on windoze. Just really ends up how much you want to spend to get hard core versions vs more limited.
Some lower cost version below.
You can look around and find some of the free or limited use software like Eagle PCB that you can use free with some limitations (Number or parts or pins, not sure). Look for some of the PCB cad software as some are free and can output DXF and other simple formats.
Just doing a search on google with 'Free schematic software' turns up some interesting links.
http://www.pcb123.com/pcb123compare.php ExpressPCB - Free PCB layout and schematic software
This has some low cost shareware versions
Best free schematic capture downloads. Easy to use, professional quality electronic schematic capture software. A vector graphics diagramming tool for creating rich, informative diagrams.
Another one you is design cad
IMSI/Design
They have some low cost cad programs and are ok for fun stuff and reasonable priced.
HTH
Sandy