Is there a way that I can find the total usage hours on a camcorder?? IS there an internal odometer inside the camcorder?

The Sony camcorders store that information internally, but only a few models allow you to access it. The PD-150 and PDX-10 have menu items for this. For other Sony models you must use the special wired service remote to read the data. You will find some info about this (in the context of the TRV-900) at bealecorner (http://www.bealecorner.com/trv900/service.html)
The camera stores the running time (hours of drum rotation time) up to 9999 hours 59 minutes in internal, nonvolatile memory. Also stored is the date (year/month/day) of initial user power on, and the date of the most recent condensation event ("dew" indicator). Memory is maintained by an internal +3V lithium battery, not user accessible. Reset may possibly clear this memory (?). You can only read out this data if you have the RM-95 service remote though.

Boyd,

Would you happen to know if the Canon 3CCD camcorders like the XL1 or the GL2 have the same features?

No I really have no experience with them. One might logically assume that the information is stored somewhere though. Perhaps somebody else can help with this? But even in the case of the Sony's, that internal information doesn't help the average user much since it can't be accessed...

Sony is one of the few companies that enables the tracking of that kind of data on prosumer level equipment.