
DOSBox is the program you will need to download to run those older DOS games. At first impression the website looks real scary. Once I got pass the ugly guy in the banner, I found a lot of good information. There is a program this that will run inside Windows. It allows you to run older DOS games in full screen mode. He also has another webpage that show how well those games will run inside his little program.
If you want to find out more about running DOS games inside Windows Vista you can go to Hackszine.