Unable to shift transmission from Park

This 1997 Tahoe 2wd with 82700 miles has recently refused to come out of the park position after the vehicle is started. Turning off the key and restarting some times relieves the problem. Usually after the vehicle sits for awhile it will shift from Park. There seems to be no correlation with the amount of driving or temperature of the engine.
any one else have this problem????

do a search of this website, or the internet for BTSI (Brake transmission shift interlock)

Thanks for the info.