ioreg -l | grep Capacity
...the cycle count information is displayed among the other known battery information. For my band new Powerbook battery, the cycle count stands at 10. Your mileage may vary...
[robg adds: A previous hint goes into great detail on ioreg, and includes a script for checking some of its values. On my machine, the output of the above command is as shown below. It takes a few seconds to run, given the length of the output from ioreg -l (try it sometime!).
$ ioreg -l | grep Capacity
| | | "IOBatteryInfo" = ({"Capacity"=3971,"Amperage"=0,
"Cycle Count"=43,"Current"=3962,"Voltage"=12493,
"Flags"=838860805,"AbsoluteMaxCapacity"=4200})
| | | | "IOBatteryInfo" = ({"Capacity"=3971,
"Amperage"=0,"Cycle Count"=43,"Current"=3962,
"Voltage"=12493,"Flags"=838860805,
"AbsoluteMaxCapacity"=4200})
Note that I have wrapped the lines by hand -- they're actually really wide single lines. If you don't set your Terminal window *really* wide, though, you won't see all the output; it gets chopped with a $ symbol. Is there a "wrap" option on grep that I'm not aware of?]

