Arduino IDE 1.0 doesn't upload to Arduino Mega 2560.
Older versions do.
zefino:
Arduino IDE 1.0 doesn't upload to Arduino Mega 2560.
Older versions do.
I wish I had known this before I started programming my Mega2560 with v1.0. 
Mine programs fine. What operating system are you using? Windows, Mac, or Linux?
I have about 30 Mega 2560 Rev 2 and 3 boards, they all work fine under Win7 64. If the driver is installed properly, then I would assume it might be a bad board.
zefino:
Arduino IDE 1.0 doesn't upload to Arduino Mega 2560.
Older versions do.
You might want to include some details. This isn't a true statement for everyone.
I have windows XP, SP3.
I thought there is a driver problem, but anything I did with the drivers didn't help.
I was desperate and I tried older version of Arduino IDE and uploading was working smoothly.
More info about the problem: when I click upload button in IDE rev 1.0, the progress bar gets filled for ~ 80% and than the program hangs. It's not possible to open the serial port any more. There is a deadlocked process "avrdude". If I kill it, IDE is responsing again and serial port is accessible.
Do all program uploads hang? Like the blink example? Or just this one specifically?
You don't happen to have three exclamation marks in a row (!!!) somewhere in the code, do you?
Even the blink example is not uploaded. RX LED twinkles a little bit and that's all.
Do you have any shields plugged in while you are trying to upload?
No shield. The question is why does it work with the old version.
zefino:
No shield. The question is why does it work with the old version.
The lock-up sounds like it is related to avrdude, which was updated with 1.0. You could try snagging the avrdude with the older version and copying into the tools directory of the newer version. It might be an interesting troubleshooting step.
OK, I will try that. If it will be clear that avrdude is the source of troubles what info can I try extract so that we know more about the core cause ? Is there any log ?
Problem solved - I selected Mega 2560 in IDE while I have Mega 1280. There is no problem uploading after selecting the correct board.
Sorry for bothering you, my mistake.
zefino:
Problem solved - I selected Mega 2560 in IDE while I have Mega 1280. There is no problem uploading after selecting the correct board.
Sorry for bothering you, my mistake.
Ah, that old 'short between the headsets' problem. 
Lefty