I have used Express PCB and DIP Trace, both free softwares available on the net. you can just random search and download them. For my application, i used the express PCB software to do a single layer PCB layout for my isp1161 chip. Express PCB is quite easy to use.. For your single layer design, i think it shoul be no problem using express PCB. anyway, user preference is subjective and ... well, just try them out and see