Be carefull with old rubber! ABC did a video a few years that talked to aged tires. Here is a link to the story:
http://abcnews.go.com/GMA/video/aged...hazard-4826897
Tire dates are normally four digits long and stamped in a recessed roundish rectangle on the sidewall of the tire. The first 2 digits are the month and the second 2 are the year (0405 would be made in april 2005). Check to make sure when you buy "new" tires that they are really new.
Before 2000, the date code had three digits so if your little code only has 3 digits then you should change them out anyway.