I have looked over for the topics people reach this blog and it seems that most people check my ARM simulators post.
I have a piece of advice. Being my self poor enough to not being able to afford any ARM development board ( though Olimex has cheap ones ) I got into this search for a simulator. I in fact do not recommend using one. If you are after getting knowledge with ARM, you probably would be better buying a cheap J-TAG and development board from Olimex ( hey Olimex, if you want to give me free hardware for this free advertisement I am not gonna regret ;-)) and using Yagarto , not a lizard folks, just a suite with all the stuff you need.
However, commercially speaking I would be willing to do ARM development from scratch, only if paid by a major company which could afford compilers like Keil or IAR. And real good debugging hardware.
Anyway, you can play with IAR and Keil demos.
If programming for hobby, please consider AVRs, their 32 bits version for example.
I intentionally did not include links for Keil or IAR here. If they want to advertise, I want them to pay me :-) This is my "demo advertisement". But I do admit, their products are excellent.