Arduino and rs232

Hi,
is there any way to transfer data to Arduino (and back) using RS232? I have Arduino with USB and I'd like to use it even on standalone ATMega.
Thanks.
(sorry for my english)

Sure, add an RS232 module:
http://www.nkcelectronics.com/rs232-to-ttl-converter-board-33v232335.html
http://www.nkcelectronics.com/RS232-to-TTL-converter-board-DTE-with-Male-DB9-33V-to-5V_p_369.html

Connect D0, D1, +5, Gnd.

If you're using for Serial uploads, will need to press Reset on the Arduino when the IDE displays
"compiled xxx of 32xxx bytes" or similar message.