AVR-Chat

Hi folks,

I'm working on a project using the atmega8, and would like to
implement more features into it.  Basically, there are 3 different
flavors for this project to control, and (now) the end user has to
select one before I send it to them.  

I'd much rather have them program it themselves.  Now, the problem is,
I didn't design it with this in mind.  <grin>

The good news, is I don't think I need to make any hardware changes. 
PD0 and PD1 (RXD and TXD) go directly to the outside world via a
connector.  A max232 interface is needed there, but no big deal.

Now, the question is, can I use these two pins to have a PC/laptop
write to the internal EEPROM?  I thought about uploading new firmware
each time, but then I have to worry about encryption, etc, etc.  So
instead, just write to eeprom a few bytes about how to control the
output pins correctly for whatever flavor the user wants.  Have the
eeprom read at startup or what have you.

Can this be done?  What will it take?  Thanks!

Ryan