Electronics 2000

Can anybody help me build a data logger. I want to take the rx and tx pins from a microprocesser and log all data that is transfered accross it. Would this be easy to do? Im guessing it would be but has anybody got an example schematic

You obviously need a processor with a UART input then a memory chip to hold all the logged data.
An EEPROM would be good for this as it keeps the data if the power is switched off.