Firmware extractor?

[redneck]

this is my first post here so i dont know if this is the correct place to post. im a complete n00b to PMP hacking. i was wondering if anyone here knew of something/some application that could extract the files out of the archos firmware update files? i was hoping that there would be something like the Zen tools for the archos.
the model i want to hack is the 604 wifi. a second question: how does a boot loader become cracked? how do i attempt cracking a boot loader safely?

thanks in advance!