As you may have already seen, RecBoot is a utility which allows the user, you, to kick the connected device(s) into and out of recovery mode.

Unfortunately RecBoot for OS X does not support 10.4.x machines nor does it support PowerPC machines. This is due to the fact that I have neither to test with, however, the source code is readily available to those that do want to create a RecBoot for 10.4.x or PowerPC. All I ask in return is that you contact me via email in regards to what you’re going to develop and how this will help. I will also be able to assist in hosting the newly created version of RecBoot.

“This handy little utility plays an important role in finishing off the downgrade.”

- LifeHacker

“In a few seconds, RecBoot would help you out of plug-me-into-iTunes recovery mode and you’ll boot right into your freshly downgraded 3.1.3.”

- FindTut

“The tool is dead simple, and everybody can use it. It has two buttons ‘Enter Recovery Mode’ and ‘Exit Recovery Mode’ , and you don’t have to be a genius to know which one to click.”

- FunkySpaceMonkey

The newest version of RecBoot for OS X can be found here: RecBoot Intel (209826)

Updated.
The above version of RecBoot is 1.0.2. It is a little bit different to past versions and I would appreciate it if you read the README.txt before commenting.

Windows Users
Looking for RecBoot for Windows? Jump over to this post here.

Linux Users
No, we didn’t forget you either! Thanks to the magic of @malontop we can now offer you a version of RecBoot for Linux! If you have any questions, feel free to contact him via Twitter. You can download the Linux version from here: RecBoot for Linux (2951)

10.4.x and PowerPC Users
If you’re having difficulties with RecBoot on a 10.4.x Mac and/or a PowerPC Mac, it won’t be fixed. It just won’t be supported at all. So, a detailed “How-To” is available here for you. Hopefully this stops ALL emails wanting a 10.4.x and PowerPC version.