Several others make real time clock chips.  Check out Epson, Dallas
(www.dalsemi.com) and Seiko.

Dallas in particular makes a wide variety of different chips.  Interfaces
for parallel, IIC, 1-Wire, SPI, etc.  They also have some sub-microamp
parts.  The part I buy and use is under $2.00, so it's cheaper than the
PIC, lower power, more accurate, smaller.

Why use a dedicated PIC?

                                Don