ok lets see if i got it if i want to program a AT89C51RD2 with the uart using FLIP from atmel then i must do what Oleg Sergeev said:
- EA is tied to Vcc.
- ALE is not connected at all;
- PSEN is connected to grounded switch (you know it: pullup resistor is presented as well);
- RX/TX are connected to COM-port via MAX232.

So what I do:
- if I need to upload my program into chip then I connect PSEN to GND with switch then power on and use FLIP;
- if I need to execute my code then I switch off PSEN from GND and just power up.

is that all? is this correct? it doesn't sound that complicated