[Al Skierkiewicz]

Found these definitions on a site this morning. They are not official but you get the general idea....
CCA Cold cranking amps. Maximum number of amps a battery can supply for 30 seconds at a temperature of 0 degrees F, before dropping to 7.2 volts. This is a more severe test than MCA and results in a lower number.

MCA Marine cranking amps. This is similar but is measured at 32 degrees and so results in a higher number for the same battery.

Amp Hours This is normally measured at a 20 hour rate. The amp hour rating is the number of amps a battery will supply for 20 hours at 80 degrees F before dropping to 10.5 volts, multiplied by 20 hours. ie If a battery can supply 5 amps for 20 hours then it is called a 100 Amp Hour battery.

Reserve Capacity The number of minutes a battery will supply a specified constant current (normally 25 Amps) at 80 degrees F before dropping to 10.5 volts.

This measure is more appropriate for an automotive application and is intended to tell you how long you can keep driving with a dead alternator.