Yupp!!
Jabber is right. ISIS is the software simulator I used.
Proteus and ISIS are complementary tools. ISIS does the simulation and Proteus does the schematics and PCB, or so. Never used that part, yet.
Unfortunately is not free though a demo version exists (don't know about it's features tho).
I am lucky because a friend is a hardware developer and use this software for his company's duties so I had access to the features needed.
I know (just took a look at the site) that educational licensees exist with 20% discount on commercial prices.
Anyway if you pm me I can give you a couple of examples of a barebone ISIS project you can use to test and try. Once you got the software, of course.
Happy if I can help and "give something back" to the community.