For starter, I would recommand the date/time chips from Dallas Semiconductor (http://www.dalsemi.com/). Those ICs are battery-powered, can be memory-mapped, and with great precision. After you are experienced, you can try to calculate the clock from your on-board crystal, which can be any number of MHz and needs a lot tweaking. Search at this site will lead you to the hints.

A starter also need to have some 8051 reference/textbooks around. Ready to be compiled source code in assembly or C can be found in those books for LCD programming, with other wide range of 8051 peripherals. Books also contain circuit diagrams and tablized LCD command sets which are usually not duplicated here.

Oliver