Hi Carlos,

you need a TTL to RS232 converter to start with, like a max 202 from Maxim
http://www.maxim-ic.com

Then you just connect TX from the 8052 RS232 chip to rx (pin 2) on the PC serial connector, RX to pin 3 and ground to pin 7.

Getting your code to talk to you is dealt with in a lot of recent postings here, please read them.

Steve