I just found this great website,

You can play all the old SEGA games online for free.

http://www.ssega.com/" onclick="window.open(this.href);return false;

Just thought i would share it.

Brilliant! the first console I had as a kid was the mastersystem, which was followed up with the magadrive. I completed Sonic the Hedgehog and Streets of Rage many many times. Thanks for sharing.