Hi, Search and download fm the following sites:

1) www.dte.uvigo.es (This is having some nice facilities to simulate the peripheral components too)

2) www.spjsystems.com (I liked this)

3) www.keil.com (Request for a free CD)

4) www.raisonance.com

Better or best depends on ur requirements. One thing is sure. But all the free versions will have limitations on the max. code size usually to around 2K or 4K. But the full functional version of the simulator from the first site will also be available soon.

Have a nice time..........