copio incollo da xda
What is Heimdall?
Heimdall is a cross-platform open-source tool suite used to flash ROMs onto Samsung Galaxy S devices.

How does it work?
Heimdall uses the same protocol as Odin to interact with a device in download mode. USB communication in Heimdall is handled by the popular open-source USB library, libusb-1.0.

Why “Heimdall”?
The flashing software Odin is named after the king of gods in Norse mythology. Loke, the software component on the Galaxy S that provides functionality to flash, may also to be named after an important character in Norse mythology, often translated as Loki. As such I have named my flashing software Heimdall, after the Norse god, and guardian of the Bifrost Bridge.

What platforms does Heimdall run on?
Linux, OS X and Windows (XP, Vista, 7 etc.)

Why use Heimdall when we can use Odin?
Odin is generally unreliable and only runs on Windows systems. Furthermore, Odin is leaked Samsung software that is not freely available or well understood by the community.

Is Heimdall safe?
No matter what method you chose, flashing firmware onto your phone has a lot of potential for disaster. We have tested Heimdall with a variety of phones flashing several different firmware versions resulting in a 100% success rate. As such we believe that Heimdall is generally reliable. However keep in mind, just like any flashing software, Heimdall has the potential to brick your phone if not used correctly.

How do Galaxy S phones get bricked when flashing?
Besides the inherent risks like power outs, accidental removal of the USB cable etc. The Galaxy S appears to be running extremely unreliable USB control software.

A failure to flash does not automatically equate to a bricked phone. However if you're extremely unlucky and the flash fails whilst transferring the primary boot-loader, secondary boot-loader or params.lfs (all quite small) than you've got yourself a paper weight that you're hoping Samsung will replace.

Please be extremely careful mixing files from different firmware releases. Don't do so unless you're certain it will work!

What Galaxy S variants has Heimdall been tested with?
We’ve tested Heimdall with a Galaxy S GT-I9000 (8 GB) from the United Kingdom and Galaxy S GT-I9000 (16 GB) from Australia. We don’t personally have access to any other devices to test with, however users have confirmed Heimdall functions correctly with the AT&T Captivate, Bell Vibrant, Telstra GT-I9000T, Epic 4G and the Galaxy Tab.

Enough talk, where can we get it?
The latest release is available here. Please read the instructions and README files included in the archives.
(eliminatelo se non posso linkare altri siti)
qualcuno ha provato questo programma? sapete se esiste una guida? funziona sui 32 bit o solo sui 64?
sarebbe magnifico non dover elemosinare pc con winzozz per flashare!