Here is a link to zelio: http://zelio-soft-2.software.informer.com/ I'm on the wrong machine so I'm not 100% certain of the link. The software is free and the smallest relay is about the cost of a couple TDR's, so it's reasonable.
I have used another make, but they charge for the software.
#206154 - 05/30/1212:09 AMRe: Looking for a simulation softeare program
You can also try Automation Direct, free software (Click), a Click PLC is about $70, you might need a small power supply if you don't have one. The programming is about as easy as it gets, I use it to teach ladder logic & PLC programming.
Few things are harder to put up with than the annoyance of a good example.