You could try www.thecontrolzone.com. This site helps with the research, compare and selection of many different products. They also have a discussion forum to further aid your search for product information.
Kieran9, to answer some of your questions,
As far as I know there are no free ladder logic programs, I believe each PLC has their own programming software. Some PLC software packages have a simulator option - I've used the Siemens S7-300 simulator and it is excellent (but expensive.
Finally...
