how to replace heater core ?

i have a 1996 camaro z28 with lt1 . my car ran real hot for just a minute and went back down . there was water and coolant in passenger foorboard . ever one says its the heater core . how hard is it to replace the heater core and how much does it cost . i have never replaced a heater core . also , how long does it take . all of your help is gratefully appreciated . thanks

The search found this...http://www.camaroz28.com/forums/showthread.php?t=552670

I,ve done this and it's really not as hard as I thought it would be. The hardest part was getting the hoses off and on the core at the firewall. Don't use the haynes manuel, they'll have you tearing apart the whole dash and its not necessary.